Police say the incident happened early Wednesday morning, when the woman was parked in the city's northwest end and a man got into her car and indicated he had a gun, although none was seen.
It's alleged the man demanded money and credit cards from the woman, then ordered her to drive to a secluded area where he sexually assaulted her.
Police say the man then drove the car to a bank and withdrew a quantity of money from the woman's account, then drove back to the area where the incident began and fled on foot.
Shaun Carlson, 32, of Toronto, was arrested Wednesday night.
In addition to the kidnapping, robbery and sexual assault charges, Carlson is also charged with forcible confinement, threatening death, three counts of theft under $5,000 and failing to comply with probation.