What do you do about a backstabbing friend?

Ok there is this girl named samantha(she is white, no im not racist LOL) that goes 2 my school rite.ok now i have this cute basketball player as a boyfriend.he puerto rican(yea i know cute rite.) oh and im black.lol.ok anyway we been together since October 12th but me and him been talking weeks b4 that. So me and samantha was suppose 2 be like best friends.well she is one of them. Come to find out this girl sent naked pictures to him knowing we go out.How backstabbing is that.Omg i can't stand her.So this morning i go 2 the band room and find her to ask her bout it.She of course says "No, i never sent that to him" Watever. she a lier.everybody is like i should talk to her about it.I ain't talking to her.Im ready to whip a gilr azz.I think it is real messed up how she would do that.UGH!! I hate messy girls that dont know how to find they own man but wait she got a man. Now wouldn't I be messy 2 go tell him what she doing? but i aint bout 2 stoop to her level. She just betta stay out mi way or ima brwak her down like a fraction!! But on the real what should I do bout her, because really fighting aint go do nothing but make me put her in the hospital!!