Any AILA attorney should be able to help you.
Attorneys are not miracle workers, they just help you with the paperwork. Either you are the immediate relative of a US citizen, a doctor of some sort, a multi-millionaire investor, or you have "won" in the Green Card lottery, or you won't be able to get a Green Card even with the very best lawyer on your side.
I pay child support and as a man I can tell you goign throufgh the court is your best bet. When we are single we become irresposible in the most important areas specifically child support due to the emotional roller coaster everyone goes through during break ups... Dont not worry about him getting custody the courts favor women in these situations... I feel that Jesus has put the following direction on my heart for you .... Fear not only believe He has seen you innyour darkest hours of depression and worry ... He is bringing things inline for you.... The Lord is going to open a door for you financially and relationally there is a man going to cross your path this year that will Love you like you never been loved and be a awsome father for your child...
You pray about this and the Lord Jesus will confirm his word with sighns following..