How can I talk to her?

Well most girls especially me, doesn't like playing guessing games. So don't try to give her hints that you like her or whatever. We like mature guys who knows what there doing and so and so. If you can't find a way to get her alone or talk to her one on one with out anyone interrupting your conversations, asking her if she wants to go out to eat lunch or dinner is great. Its just a friendly get to know each other or a way to get her alone to talk kind of thing. Of course you should have a small talk with her first, show her you have a sense of humor, and that you really do have a great personality. don't over do it though.