1. Lawyers do not execute affidavits. They only furnish their legal opinion which is called "Lawyer's report'' and which can be filed in a court of law.
2. It is a fact that an unaffiliated qazi cannot give a khulanama. If the woman has petitioned the court the court alone can give a legally enforceable finding on the issue. The khulanama given by the qazi can be challenged in the court which can quash it as illegal.
3. You may obtain the required report from any lawyer.