I like someone and she likes me but i like someone else to. I NEED HELP?

I need help. i have been crushing on a girl ( ashley ) that told me she liked me. and i told her i liked her. And the other night i was hanging out with ashley and the girl i have had a crush on for the past year ( lisa ). About 4 months ago i told lisa i liked her alot and i talked to her for 3 hours straight on msn. And she said maybe some other time. so now i really like lisa again but i feel bad because i told ashley i like her back. so i like both of them but i like lisa more. And lisa and i are going to the same higschool next year and i only have a quarter left with ashley...HELP ME. what should i do. Lisa is someone who i can tell anything to and she can help me with things like this. and ashley is just a close friend. And lisa is going out with some one now. i told lisa what i am telling you know. she said she likes me to, and that i could go out with her next year in highschool or if something goes wrong with her bf now. so lisa likes 2 people to me and this other guy pls hlp