Girl said she would date me, but has a boyfriend?

[Brogan]

Hey people,
I know this girl who I know already has a boyfriend. Her friends told me that she met him online, but has never actually met him in person.
When we were both talking on Facebook, I asked her what she honestly thought of me, and of her points was that she would date me. Another thing, her friend (my friend also) asked me if I liked her. I don't know if she told our friend if she she likes me and asked to see if I liked her, or if she was curious.
Back to my friend, she told me that she might break up with her boyfriend since she is a bit suspicious of him cheating, she explained the situation and I understood immediately.
I don't know what I should do, I am not desperate for her to go out with me, but I want to her to know somehow that I am available if she needs, or wants me, if you know what I mean?
Hope you guys (and girls) understand most of what I have mentioned above, and that you can give me advice about what I should do, thanks.