Lookup A Withheld Number?

Yesterday afternoon I received a message on my voice mail from a girl who seemed to desperately wanted to talk to me. I remember her from a party a few weeks ago and she said she wanted to talk to me more because she had a great time. She seemed to be excited/nervous about calling me and really wanted me to call her back. The only thing though is she was calling from a withheld number and I don't remember her last name. She also left me a phone number but it appeared to be 8 digits long in the message. I understand that this could be some sort of prank, but judging from the girls tone and the fact that she knew my name makes me almost positive it is legit. Is there anyone/anywhere I can contact to find out what her full number is? Please help. If this is real I'm very interested in getting back to them! thanks!