Shall i get this girl out of school? teachers>?

this girl i have known since primary school has been bullying me, she is one of them rebellious, popular people who is mean to everyone exept her friends. so anyway, we got into an argument, all i said was that she is a liar. and i didnt even say it to her, i said it to my friend on msn but she told her. So, she puts this liar thing against me and everyone is on her side but what they dont know is that she has called me.. A rat, a ****, a ******, ginge, a loner, ugly, fat. also, whenever i see her at school she goes "EWWW". and today she called me a rat and pushed me and then on the bus i fell off of my seat, and she was with two of her friends, her friends laughed a bit but she was like "AHAHAHAHAHAHAAAAAAA" and then i said calm down she said "shut up you rat, you cant tell me what to do." and i have been ignoring her for ages but she still wont stop, and i cant avoid her, because she hangs around with some of my good friends.