how to get further than just facebook chat?

a girl and I have known each other on facebook since 2010.

since around december last year, we have really started chatting much more and she helps me with learning a language. Furthermore, she often sends pictures of herself (which I like) and we talk about various things (small talk really). I think it's fair to say a friendhsip blossomed there.

In May I had to visit her city, but she didn't want to meet (for reasons I don't know). I was devastated but decided not to give up on her.

Now we are still chatting on facebook regularly and I would say all is well. But nothing much happens and I really want to change that... Start talking on a deeper level. How can I make it more exciting, and how do I suggest maybe chatting to her on Skype?

Call me crazy, but the girl means a lot to me, and she knows that (for example, she likes me to compliment her on her latest photos and sometimes there are messages which show she thinks about me).

I really want her, but the signals are so mixed. I can't see anyone else in my life but her. Don't want to lose her.