You don't see each other enough. I don't like being demanding, but here's the thing: if you can't get this thing off the ground RIGHT NOW, she could easily move on very soon. I've seen it happen too many times. That hug was the moment to establish communication and attraction. You're nearing the end of the relevancy period, and this is where the other guy she gets to spend more time with that just started talking to her becomes an obstacle you can't overcome.
Numbers and Facebook friending are the same in the modern age. A girl typically won't give you her number or accept your request unless she wants to. Send her the request, talk to her on messenger, schedule a date. This is your only option for assured success. The longer you wait, the sooner interest may fade.