HELP!!! GET HER TO LEAVE ME ALONE!!!?

the new girl is driving me crazy!! at first i liked her but now im not so sure!! she tells the awfullest jokes, jabbers on about random things concerning her family i dont really care about at about 90 miles per hour at a volume of about 90 for about 90 minutes, thinks she's bilingual because she say "hola" and "si," looks really weird, and the worst part is, SHE CHOSE ME AS HER FRIEND!! thats the problem, she's not popular, in fact, she has no friends other than me, so she constantly follows me around like a pathetic, stray friendless puppy, yapping at my heels and showing me her big, buck-toothed grins while i have to suck in my breath just to keep from screaming. i ask her why she doesnt have other friends and she claims she is too shy to make other friends and that i'm the only one she needs. my other friends cant stand her and i dont blame them. im about to go NUTS!! what do i do, tell me what to do to get this pathetic, friendless little insect to stop following me around and find friends somewhere else!!