Your situation reminds me of a few sayings:

"Just because someone doesn't love you the way you want them to, doesn't mean they don't love you with all they have."

And one of my favorites (and most true): "The worst way to miss someone is to be sitting right beside them knowing you can't have them."

I think that by giving her space and NOT talking about your guys' problems or talk about when you will get back together, but just by being there for her and being your normal self, will show her how much you truely care. Since she knows you want to be with her, if she sees you go out your way to make things comfortable for her, she might really appreciate it (should!!).

Do you guys still hang out? If so - don't ever mention "us" talk. Just try to fight your feelings to want to talk about your problems, and do whatever you can to make her comfortable and enjoy herself, and enjoy yourself as well.

GAH - I'm not able to write what I'm tryin to say here...