A father trying to obtain rights to his daughter

My boyfriend and I are in the process of seeking legal advice to obtain rights to his 19 month old daughter. The mother is civil only when we bend over backwards and do what she wants. She told him before she was born that she'd never use his daughter against him, but has been a nightmare since the day she was born. I've been there since she was 4 months old. She doesn't believe he'll go to court. We are currently only seeing his daughter 6 hrs a week and no holidays. He doesn't make a lot of money right now, but will be finishing school early next year. Paternity still needs to be established.
Does this mean every penny he makes will probably go to child support? We are just trying to do the right thing, we want to see his daughter but be able to afford living as well. Any advice?