How to avoid this trouble maker next year and stay out of drama?

There's this girl that I used to be best friends with that I now hate. All she does is talk about people (including her "friends"). She does this but is all talk. The minute you confront her about it she either denies it or tries to act big. She just doesn't stop. I had 3 classes with her this year. I've got into it before with her and I've even slapped the **** out of her because she went too far before. But here's the thing. After a while she'll always try to be cool with you. But still talk about you. She'll try to be friends, hang out with you, be cool with you, be cool with your friends and then she starts something and it happens all over again. I'm already going to arrange for her to not be in any of my classes. How can I get for her to keep my name out of her mouth? And also avoid her and never speak to her again? I just want for her to act like I don't even exist . Never speak of me never worry about me & what I'm doing.