Slandering.. need help and advice what to do THANKS :D?

Alright so this lady who was my boyfriends mothers bestfriend will not leave me alone.. She seems to think that I was trying to come between them which is not true.. i work at my boyfriends mothers salon and I have heard from MANY clients i have heard she is putting me down telling people i am a slut.. telling people that my boyfriends and mine son is not his... i am really not like this at all i am telling the truth and this is why i need your help.. she is starting to blame me for things that I could get in alot of trouble for doing.. and i am afraid for my son and for me this is emotional draining but i feel like if i were to go to the police she would just say that i was try to do the same thing to her.. i feel like it would do nothing and i am just sick of it any suggestions?? please help thank you