What do I do if i hit my friends car?

So i was backing out of the parking lot at school today and like the one time in my life that i didn't go super slow and look attentively both ways, i hit my friend (well she's not a good friend but a friend none the less) So i hit the front right side of her car and it sort of dented the car on either side of the tire and knocked the turning signal out a little (it still works and stays in its socket). She said don't worry about it because shes going to work and it's an old car and her mom probably wont even bring it in to get fixed but i feel super bad. I offered her my information but she said she probably won't do anything with it. I don't have a lot of money but i told her i'll pay her in installments if she gets it fixed. How much would getting some dents out of a car and a new light cost.. The basic structure is still intact but idk if she would have to replace that whole section or what.
on the scale of how bad it is .. it's probably somewhere between this (not as indented)...
http://i89.photobucket.com/albums/k233/sacredcows/CarDent.jpg ... and this
http://i130.photobucket.com/albums/p264/420dent/Nasty%20Dents/civicdent.jpg