how long to finalize adoption???

I posted this on the Oklahoma board but havent got an answer. So I thought I would try hear. My work gives an adoption reimbursment after the adoption is final. We have to send in a copy if the birth certificate with our names on it. My question is how long does it take to finalize an adoption? I would like to know specifically for Oklahoma since I know all states are different. I have searched the web and cant find it. I have thought to call my lawyer but at 200.00 an hour 28.00 minimum I decided this wasnt a 28.00 question and I would try my luck here Thank you Julie