It sounds like the girl is into you.
This is how you might get her:
She liked you. She knows you liked her. Be honest about it. "Yeah, that chick was cool." That's all you have to say. Only bring this up if your friend asks you about her again.
Here's another approach. You can tell your friend, "Hey, make sure that girl comes out to the next party. I want to see her again." This is a romantic and ballsy thing to say, which should make your friend excited about playing matchmaker. It's always cool to help people get together. When she talks to the other girl about you, it will be instant social proof.
1. Have the balls to be honest and be a little vulnerable.
2. If you have some basic IOIs, just assume she really likes you. You are awesome and she can't help feeling that way. This keeps things fun and non-needy.
3. If you make a move on the girl and she resists, do not worry. "No pressure, babe." Talk about something else if you're still in the interaction. If it's time to say good night, say, "See you later.

" Sometimes, a girl needs a few days to think, after which time she may decide she likes you.
And remember, the most important and basic IOI is that the girl is still there talking to you. Really, that is the only IOI you need.