Child custody attorney and court fees

I am currently trying to get custody of my son due to unstable living environment and abuse with neglecte. He is a year and 2 months old and lived in 7 locations in his life so far. The mother has already signed one of her kids away to his father. I can't gather the funds myself sue to my own bills and child support on my own kids. I am wanting to provide a stable home life for him and give him a better future. Anything helps and would appreciate any help. Thank you and God bless