Where can I find a lawyer that will file papers with court giving her full custody of son?

Son was born 02/25/2010. Paternity was established and she receives child support. Father has never wanted to see the child but now almost 3.5 yrs later he does. She is concerned about child going with him because there is nothing in place saying she has full custody. She is afraid he might decide some day to not return the child. He has agreed to sign whatever papers she wants him to. She doesn't have much money(working for min wage) but needs something in place. Legal Aid wont help because there is no domestic abuse involved.Is there any lawyers or law students in the area that would help her for cheap? Help us please.