help please

okay guys need some advice. my bf ex wife just called me and told me she didn't want her daughter anymore she was dropping both of their kids off to live with us. we have been keeping notes when they come for visitation she has to be harassed in order for her to come get them I have had to miss work a few times because she wouldn't come get them. this weekend the five year old daughter had marks on her neck and told me her mom grabbed her by the neck we both work but just moved and trying to get everything in order with our bills we know she won't sign them over and we don't have money for a lawyer