Forget the fact that you don't know how much they have for a second.
She backed into your brand new car and left a note thats cool and all, but this is business and you deserve to have your car restored to "like new" condition. It is not you being a jerk asking for money, don't feel bad about it. It is part of them having to deal with the fact their daughter is now growing up and driving and these things will happen. You don't have to go overboard and over charge them but you need to make sure you are completely satisfied with everything before you are done with dealing with them.