I can not tell if this girl likes me?

Okay im now in high school and this girl and i have benn in the same school for 3 years now, and i cannot read her. Okay last year i asked her out via facebook... i know, i know, that was bad but she was always coming up behind me and hitting me. Plus she would always go out of her way to change her opinion to mine. To cut to the chase she turned me down, but for a year now she has had her friends watching me, and whenever i am hanging with friends and shes around. They say she is staring at me. What should i do...?