Most Helpful Girl
I'd say continue to be confident, smile, and find interesting topics to discuss with her when you have the opportunity. Find out her hobbies, what she likes etc. She will notice the little things. Since she is confident... make sure you have good eye contact. Do a good job at work, show pride in your work. That show maturity. But don't change who you are... just be confident. The little things you do mean a lot!
Most Helpful Guy
You will have to show her otherwise in this ego (misconception) you can't get her. I think she's losing interest a bit. It's the right time to approach her. To give her surprise.
Good luck :)