How can i deal with all this drama!!?

this girl who i really despise got mad at me last year because i didnt add her on myspace! honestly, i HATE her! i know, i know, hate is a strong word, but shes made going to school terrible! last year, she tried to start a fight with me IN CL! of course i was just lik "SHUT-UP! we are in cl!" and ever since then she gives me nasty looks, tells ppl i start rumors about other people, and tries to make it so noone likes me! the reason i ddnt add her was because she talks about her "best friends" constantly behind their backs and starts drama and personally i dont want to be around that! today, someone asked me if i startd a rumor that this girl, we'll call her cindy, was gay! cindy is the mean girl's close friend, so i beleive it was her, how can i get this girl to stop!!??