I am being stalked.......wot do i do?

i made an aquaintance at college and swapped phone numbas etc....this person has bombarded me with txts (63 in a day one time) an facebook messages...i have had to block 5 different facebook users that this person has set up and have managed to bamboozle her regarding my phone numbas, but now she has started harring a mutual friend in an attempt to get my fone numba. I feel bad for my friend now and to be frank, quite freaked out....this wierdo has even resorted to threatening me wiv all sorts if i wont be her ''friend'' (wierd!!) i have told her i will go to the cops but it makes no odds to her......i even told her straight that she is a stalker and i want nothing to do wiv her an she still wont stop......shes like sum sort of stalking terminator that cant be killed!!! Ha!!! I joke but its really quite scary......aaaaaarrrrrrggggghhhh.......H…