BUENOS AIRES – First lady Cristina Fernandez de Kirchner swept to victory in Argentina’s presidential vote on Sunday, the first woman elected to lead the country. “We’ve won by a wide margin,” she told the Argentinean voters in a speech at her campaign bunker as exit polls and early official results showed her with enough support to take a first-round victory and avoid a runoff election next month. Cristina Fernandez de Kirchner is Argentina’s first lady and presidential candidate senator.