How do I deal with demons?

They've gotten a whole of my sister and now I believe they're after me. I continuously have impure thoughts about women, very impure and sinful thoughts. I've tried to escape these nasty thoughts but the keep coming back. It started when my sister and I moved into a dorm together, slowly she stopped going to church with me and started going to clubs and devoting much of her time to sin worshipers. Eventually I caught her and another woman in my bed sinning together. When I told our parents about this, they stopped paying for her college and we eventually parted and I began living on my own in a small apartment. This is where I believe I had my first encounter with ual demons, they started to draw me in by the television. Showing images of other women, I had no choice but to throw my television out the window. But that didn't stop them, they kept putting impure thoughts into my head every time I come into contact with another female and It has gotten so bad that I moved all the way from maine to alaska to escape these demons. These thoughts stopped for 2 years, but I'm afraid they're back and stronger than ever. I've even masturbated thinking about women. Please, how do I deal with these demons once and for all?