@ezdarnell,
You have no choice but to wait since you don't have her number. I wouldn't recommend approaching her in her workplace again.
Personally, I would have been very uncomfortable if someone had done that in public in my workplace. It would lead to a lot of teasing from my coworkers and that was never a happy place for me.
If you had found a way to pass your number on quietly - or had your brother do it - it would be easier to approach her again. Now there's no good way to do it without other people paying attention.
I'm definitely on the 'that was too much' side of this.