i am in need of some help

I am a full time step parent of 3. I have raised them for the past 5 years. their bio mom has been in but mostly out of their lives for the past 5 years. Approx 10 months ago friend of the court begain garnishing her wages for child support since she had never paid us in the past. After the wages had been garnished she began showing up again taking them every other weekend. She now has decided to take them for the entire summer with us only having them every other weekend. Which the kids wanted to try out because the still believe in their hearts that she is a decent human. well we are now in our third week of my husbands ex having the kids. Last weekend was our first weekend with them. My stepkids are living in a 2 bedroom apt. with 4 adults and 1 child ( makes 4 kids together including my kids) while their mom and boyfriend sllep on a bed my Step kids sleep on the floor, she does not provide them with lunch and she and her friends peer pressure the kids into doing stuff they know is wrong ( i.e. someone called the wrong phone number and the adults of the group tried to get the kids to curse into the phone) I feel like my hands are tied. What rights do I have as a step parent. she will not let me talk to the kids if I call over to the apt. and yesterday she called and stated she was out of gas and wanted me to sign a check for her. I refused but told her i would take the kids out for dinner until she resolved her problem and she told me she would never give them to me because they are not mine!