Police said the woman brought her six-year-old daughter out to the car around 6 a.m. on Marbury Road in West Kildonan.
She put the girl in the car was dusting snow off the vehicle when a man she didn't know came up to her and demanded her keys.
When she refused, the man revealed a knife and stabbed her in the lower body, according to police.
The woman managed to get her daughter out of the car before the man drove off.
Her injuries were not life threatening, police said.
Police said the man was wearing a white jacket and may be driving the woman's 1998 green four-door Honda Accord. The vehicle has the licence plate GMX 393.
Anyone with information is asked to contact investigators at 204-986-2848 or Crime Stoppers at 204-786-8477.