600 doesn't sound bad for a new fender and paint. I was recently hit and had damage to my door, fender, and bumper all needing repaint, and it came out to 1200. The wheel added another 200. The easiest way to find out about the paint/crack is to take it to a good PDR shop and see what they suspect. They'll be much better at assessing than us.
Sorry about your luck
Sorry about your luck