>>1
You have her number. While it doesn't say much, at least it says that she doesn't hate you, so you're not on her bad side.

For going out with her, seriously try to find a nice and comfortable cafe, preferably with couches so you 2 can sit near each other, or at least sit comfortable. If cafe is not an option, parks are always a good way to spend some time, wandering around, sitting on a bench etc.

What I have to tell you, is, do NOT, under any circumstances, utter the cliched words "date", "bf/gf", "love" or something like that. You see, this whole thing is like a game of cards. You and her both have cards in your hands, and you have to slowly play them. She plays one card, you play one card, maybe she'll play a negative one and you can react accordingly. Don't lay out all the cards at once, you'll be shooting yourself in the foot with this