Car accident, who's at fault?

My girlfriend was driving my car (which is in my name, but bought for her). We pulled up to a intersection, the light was red, the car in front of us turned, so she pulled up a little, still while on the brake, to check to see if she could turn as well. There were cars coming, so she stopped. When she stopped, the car behind us bumped and damaged the rear bumper. The lady who was bumped us was driving a rental car and had insurance. My girlfriend, Carmen, did not have insurance because it was a brand new car. The Officer tried explaining to her that no matter how new the car is, you NEED to have insurance. Well my question is since Carmen did not have insurance and she is not at fault, what will the other drivers insurance cover, or will they cover anything at all?