Lawyers knowledgeable in the area of family court/adoption?

What's the best way to defend myself in this situation? I had a child six years ago with someone. I saw her for the first six months. then, the mother stop letting me see her. That is, she banished me from her residence and refused to meet me in public with the child. Although I filed a petition for visitation, I did not follow up on it. The reason is that she told me that if I kept up she would get child support from me and move away. From that time on, the only effort I made to contact the child was to send gifts on X-mas and her B-day. My mother saw her out at the mall on a couple of occasions and asked he rif she would bring the child over. She said no. My sister also sent her some emails; but the child's mother wasn't interested in having a relationship with her either. One time I called over there, only to find out that the phone was disconnected. Evidently, the mother married some man two years ago. Now he wants to adpot the child and give her his name. I signed the birth....