How can I get full custody of my son hes 2yrs old and im worried about the environment his moms putting him in?

were in the process of getting a divorce and we had a deal were id watch him during the day but she just moved across town and her car broke down and says she cant get him down here anymore and i dont know whos watching him or what when i came to move out her apt cause it was in my name and she was just livin ther she didnt pay rent and just left me with the bill and the bills were in my name 2 and she didnt pay that either she not a us citizen thats why i had to put it in my name and i have been a great father i take care of everything he needs what can i do to get him in my life i know the courts favor the mom at that young age but i know hed be better off with me