The lawyers want a Canadian appeals court to reverse a judicial review by the federal attorney general that supported the extradition of Monique Turenne of Winnipeg.
She's charged with first-degree murder in Florida. Her husband, Canadian Air Force Major David Turenne, was beaten to death outside their Panama City more than eight years ago.
He was stationed at Tyndall Air Force Base in Florida's Panhandle.
Monique Turenne's former lover, retired U.S. Air Force Master Sergeant Ralph Crompton, was convicted of first-degree murder and is serving a life sentence.
Turenne initially denied any involvement but later confessed to Florida police she set up her husband to be attacked by Crompton, but she fled to Canada and says she isn't coming back.