Quit focusing on this one girl. Talk to, date, hang out with a bunch of other females. By doing this you will seem like a much more attractive and interesting person and in turn may spike her intrest in you. You will also have a bunch of dhv stories about how you hung out with this girl went out with this other girl.
Also quit making excusses for yourself why you have not talked to her. Just fucking do it.

Search out a bunch of the matreial on this site. There are tons of posts about what to do in a situation like this.....
Hope this helps.