"She lives with other addicts and I hate the environment she seems to be easily influenced now a days and it's like as soon as she goes back to that house she becomes someone else."
She's using every time she goes back there. And the solution to that is NOT to have her move back in with you...she'll find a way to use no matter what.
Getting YOU some help is crucial. Therapy or Al-anon...this board is also a terrific resource but we're still just strangers on the internet, we can't be there in person. But if you read the Friends and Family section, you can see how often this happens and that you are not alone.
Sending you a hug.