If you have her phone number then DO call her. I think she is thinking about what happened, she is not in a rush to reply on your Facebook message. She is still evaluating you, she didn't really get a chance to do that at the meeting. But the good thing is that very few people would give their Facebook to strangers... only Facebook junkies would...

if she has like 500 friends and her facebook is full of crap like kisses, funwall, zombies then she is likely a junkie