I would call her and tell her someone left a phone number on your vehicle to call them.
If it's her and legit, she'll know what you're talking about.
If she don't know what you're talking about, ask her who she is, and then try to figure out who she was from the party. Maybe it's someone trying to get you and someone together. Maybe it's a prank, but you may still get a date out of it.
Talking about the party will give you a chance to talk and move towards a date.
DON'T ASSUME you know who you're calling. It might be a different girl, and she's not going to be interested if she thinks you're calling hoping it's someone else. It could be a better opportunity than the girl you think it is.
Ask her if she'd like to go out. Don't go to a movie. Offer to go to someplace cheap. Dairy Queen is good if you have one that serves food year round. Sit, have food and an ice cream, and BS.
You could take her bowling. Tell her you suck at it, but it'll be entertaining and give you a chance to talk versus a movie.
Do something fun, cheap and entertaining. Don't try to impress her. She'll see herself wanting to hang out with you because you're being yourself and your interested in hanging out with her, not taking her places to try and impress her.
Remember, the first date is just an interview for you both to decide if you want to go out again. Be yourself, or you'll never really be happy in the relationship.
Let us know what happens.
PS. I agree with entering the number at
www.whitepages.com (reverse lookup). If it's a home number it may give you a name. More than likely it's a cell, but it doesn't hurt to try.