Fellas, Rozay again with a question!

Tonight I saw social dynamics at work and was able to attract a very hot girl. I will spare the details, but I was given serious IOI's, she qualified herself to me a few times, and we built rapport very quickly. Unfortunately, she left prematurely and at the time I was in a conversation with another group of people, though when she said goodbye she made lasting eye contact with me and walked out the door. Needless to say, I was unable to get the N close.

I'm anticipating a Facebook friend request within the next few days (she literally looked me up while I was there) and I'm wondering what signs I give by contacting her with a Facebook message to get a number close? Is this a bad move? Do I wait until I run into her again? And if I do send her a message, do I immediately go into plans for seeing each other again? or I have a conversation? Let me know what you think.