Help with adoption.

Hello all, my name is Keith and this is my first time here. I was wondering if anyone could help me out with some advice. Me and my wife have been married for 6 years now. Before we got together she had a daughter. The "father" legally sign over all his rights so he would not have to pay child support. So my wife has sole legal custody. The paper work was filed in Nevada. We still currently reside in Nevada. Me and my my wife have talked it over with my daughter who is 9( she is my daughter I have raised her since three and she calls me dad ) and she is ready to change her last name to mine. So my question is how do I go about adopting her legally? I talked to a lawyer and he said it would cost $1500. That seemed outrageous to me since the adoption would not be contested, and the hard part of getting the bio dad to sign over rights is already done. So is this something I can do on my own? Or is 1500 dollars average for this sort of adoption? Any advice would be greatly appreciated thank you.