First things first. She isn't off limits.
Secondly, you have the advantage of already being past the approach. You can invite her to go somewhere/do something with you, and she won't think anything strange of it (and if she does, blow her off!). There is no reason why she can't walk away with a re-kindled interest in you. If she doesn't, big deal; what doesn't kill us makes us stronger and you have learnt something!
I'd brush up on your techniques, work on a few routines, and maybe you can take her for a coffee (even suggesting a walk around the college for her to get her bearings afterwards, if you think just a coffee would sound weird). It shows your helpful, and after the coffee, the only place she MAY want to see if your room
