How much to repair collision damage?

My wife had a minor arguement with someone in an SUV today. They both tried to merge into the same lane. To be honest, I'm not sure who was at fault, so I agreed (verbally) with the other driver that we would each pay for our own vehicles. A few questions:
1. The only damage to my car is the driver's side front fender (as far as I can tell). Its mostly just scratches, but there is a fold about 1/2 inch deep in the wheel well. Assuming that I'll need to have the fender replaced at the VW body shop, any idea what this might cost?
2. By the time I spoke to other driver, she had already called the accident in to her insurance. She said that the only damage to ger car was a crack in the small piece of plastic around her wheel well, and she's prepared to pay for that herself if I take care of my damage. As she's already called her insurance company (Geico) can we drop the insurance aspect?
Jeff