This is what I know about this subject, but I live in Michigan. I don't imagine that the laws vary too much on this...My situation is very similar except that my ex has never made any attempt to come and be near his daughter. I wanted to start the process to have him relinquish his rights. I can tell you that a) your custody case worker should be able to refer you to a good family law attorney cause you're gonna need one. b)legal aid will NOT help you at all. They don't deal with family law, period. c) It's a lengthy, drawn out process that can sometimes turn into a battle. That's the way that the courts have designed things so that the child's best interests are met, which normally means that both biological parents are a part of the child's life. d) Prepare for discouragement from people. Apparently the courts frown upon having a parent relinquish rights unless someone is in harms way or in some danger, and even then....
I don't know that any of this helps, but I have been there and I wanted to share what i know. We decided, for my family, that we would wait until my partner and I were married and then when he was ready, he petitioned to adopt my daughter and all we had to do was get approval from her father, ie: he had to sign off on his rights. That, of course, is another story entirely
Good luck to you.