Per the woman's statement to me:
she placed the shopping cart between our cars because she knew it was a windy day. she turned around (taking her hand off the cart) to put her child in the car and the wind blew the cart into my car. She is now claiming that she is not responsible since the wind blew the cart. Is she not negligent for leaving the cart out of the rack on a windy day and positioning it in a manner that could cause damage?
I failed to mention that the incident was witnessed and the woman admitted fault and gave me her insurance information. her story changed over the course of 2 weeks.
If it was a windy day, the argument can be made that is it reasonable to foresee that leaving a cart unattended would blow away potentially into another car. Specifically, this woman should have been aware it was windy and should mind her cart accordingly. I would obtain her insurance information (her automobile insurance to start with) and proceed with her insurance company to get your matter dealt with.
I agree with Chris. If her insurance company doesn't take responsibility you'll probably have to take her to small claims court. But, I'm not sure if it is worth your time and expense. Many counties have a small claims clinic, so filing that sort of claim is pretty "easy."