For 48 turbulent hours she was the victim of a conspiracy that left the future of Malawi hanging in the balance. Then Joyce Banda made a critical phone call to the head of the army, asking if she could rely on his support. He said yes. And at that moment her place in history was assured.

“You ask how I feel to be the first female president in southern Africa?” she said in an interview. “It’s heavy for me. Heavy in the sense that I feel that I’m carrying this heavy load on behalf of all women. If I fail, I will have failed all the women of the region. But for me to succeed, they all must rally around.”

Banda’s dramatic rise came when President Bingu wa Mutharika’s increasingly autocratic rule was cut short by a fatal heart attack earlier this month. As vice-president, it was her constitutional right to replace him. After overcoming resistance from Mutharika’s powerful allies, she has now set about rebuilding the country’s shattered economy and pursuing a cause close to her heart: women’s rights.

The 61-year-old first rose to prominence as a champion of female empowerment, founding organisations including a microfinancing network for thousands of women in rural areas. She says her own experiences of marriage have driven her crusade.

“I got married at 22 and remained in an abusive marriage for 10 years,” she told the Guardian during a visit to Pretoria, South Africa. “I made up my mind that that was never going to happen to me again. I made a brave step to walk out in a society when you didn’t walk out of an abusive marriage.It was mental and physical abuse.

“Two years later I got married again to my husband who was a high court judge in Malawi. For the next two, three years I moved from zero to hero: I was running the largest business owned by a woman in Malawi, in industrial garment manufacturing. But when I looked back his fingerprint was all over: if I wanted training, he paid; if I wanted a loan, he came with me. Because of his status in society everything was easy for me, so I had succeeded but I had succeeded because I was privileged.

“And that’s when it began to worry me. I began to think about those that were in my situation that were not able to walk out of an abusive marriage, or maybe those that did not know where to go, that were in a single headed marriage, or widows. I was thinking what it was I could do to reach out to them.”

Pointing to Ellen Johnson Sirleaf of Liberia, Africa’s first elected female head of state, Banda added: “Africa is changing in that regard and I hope you know that we are doing better than most countries. America is still struggling to put a woman in the White House but we have two, so we’re doing fine. This is what people did not expect us to achieve but we have.”

Compared to her strait-laced predecessor, Banda dresses colourfully – her spectacles have sparkly Dolce & Gabbana designer frames.

In the interview, she revealed the inside story of how Mutharika’s sudden death pushed Malawi to the precipice of a coup. By 6 April, the news had spread worldwide yet there was still no official confirmation inside Malawi itself. The cabinet met secretly in an attempt to thwart Banda and install Mutharika’s brother, Peter, as acting president.

Ministers held a press conference “in the middle of the night” on state television, she recalled, “telling the nation that I had no authority to act as president, that they were making arrangements to take over, that after all the president was OK and recovering. And all the while he was dead the previous day at 12 o’clock.”

On 7 April, South Africa confirmed Mutharika’s death and Malawi’s cabinet sought a court order to block Banda. It was then she phoned the army commander, General Henry Odillo, who sided with her and stationed troops around her house. This was the pivotal moment.

“By that time the chief justice and some judges were sitting at Peter Mutharika’s house waiting for the court order in order to swear him in,” Banda continued. “All cabinet ministers were there too and all members of parliament were there as well. But somebody called one minister to say, ‘We don’t know whether you know what’s going on but Joyce Banda is here and now it’s looking real, so whatever you are doing elsewhere will be looked upon as treason.’ At that point 15 ministers abandoned that place and came running to my house.”

Ministers and MPs bowed to the inevitable and rallied around Banda. But she could not be sworn in without the chief justice, a Mutharika loyalist who protested that he did not have his robes and wig. A car was sent to fetch them.

Banda observed: “The fact that the army stood up and restored order is a sign that we have matured. The army had an opportunity to take over – in fact, I am told some of them were being persuaded to say, ‘If we can’t have it, she can’t have it – just take over.’ But they resisted that temptation and to me that is the sign of maturity and a maturing democracy.”

Banda has wasted no time in appointing a new cabinet, sacking the central bank governor and police chief and reversing her predecessor’s most unpopular decisions. She has pledged to follow IMF advice by devaluing the national currency by 40%. “We brought this upon ourselves because of our carelessness and arrogance.”

This included falling out with a leading donor, Britain, whose high commissioner was expelled by Mutharika. We have assured the UK that what the high commissioner went through will not happen againand he will be respected , she said.

Banda sounds less enthusiastic, however, about singer Madonna, who has adopted two Malawian children but scrapped the building of an elite academy for girls, announcing plans for 10 schools instead.

“Madonna came to Malawi and Madonna came to build a school, an academy like the one Oprah [Winfrey] built here [in South Africa], but she changed her mind so I have a problem with a lot of things around the adoption of the children and the changing of the mind and then coming back to build community schools.

“She’s not interested in investing any more – she has closed her offices in Malawi. We have accepted her position and we respect her decision and I personally don’t have any further comment about that.”