I would go in and have some fun with her. Don't worry about the out come, that is added pressure you don't need.
Tease her (as CGE333 said), make her laugh, give her a thrill, get her blood flowing, make her feel happy she decided to come into work that day. Once you start doing all these things, she will start to assoicate these good feelings with 'you' (this is very powerful).
Once you see her feeling comfortable with you (she'll drop hints, look for them), then get her email or number on your way out the door.
Note: A girl doesn't like you over time, it doesn't work that way. If she decides to F your brains out, it happens very, very quickly, so be ready.