You'll never know if you don't ask. We've all been here in this position. In my case, I never asked. 6 years later I did while both of us were attending college, and I got the answer I didn't want to hear. If you can't guess, she said, "why the hell did you wait so long, I would have said yes" :( At that time it was waaay to late. I guess to answer your question, whatever you do, don't do what I did. The waiting game don't work.
And don't go to her brother for the phone number. Just ask her yourself.
In my defense, the way the chick is today...Thank goodness I never asked her. Thank you thank you thank you!