How can I give my rights as a father up? also, How much would it cost?

After my friend had a child, she could not find out who the father was. numerous paternity test were taking. (Court issued) Three years later, the court made me take a test as well. It was postive.He is now five years old. I pay child support and have not had anything to do with him. Have i had personal contact with him? Three times in the past five years. Lets not forget i didnt even know of him until he was three years old. Also its not because Im not aloud visitation, it is because i personally do not want anything to do with him. It may sound rude but Its the truth. I have a five year old daughter and we have been together since day one. Coming from my perspective and feelings and heart. She is my girl. Again, i was approximately the tenth male to take a paternity test within the first three years of the boys life.? She is saying she is going to take me back to court, Is there ANYTHING i can do to give up my rights? I know I will never have anything to do with them even if i cant