First you need an explanation of how she ended up at the house. If she was given permission to leave then she may not have done something wrong.
Bekind is correct about dealing with legalities of her legal residence. She doesn't have to have her name on the house to be a legal resident there - in fact I believe you are married? If you are you can't just toss her out, or refuse her entrance. You can evict a girlfriend but you can't evict a wife.
It sounds like she has been cooperative with leaving the home before and I hope that continues. First thing first though, find out how she ended back up at the house. If she left the rehab without permission she might be subject to being released.