hello pbunyan, this is from my own experience please listen:
Girls don't say things straight sometimes, especially when they're confused about their feelings.
The best thing you can do in this case is just cut any communications with her, at least for a while. Keep talking about the same thing or pushing her to confess won't help neither of you to make up your mind. And follow em3bilko's advice, stay busy because you're now probably thinking in loop mode, that son't help you in any way.
Getting her to tell you the truth is not the first thing you need now man. It won't make you feel any better believe me. It's very hard to face this, but you will succeed. This situation may get pretty horrible at this moment, I've been there not once but a few times. Just think about this: the pain won't last too long, you will recover. The sufferin is just temporal. Serious.
In less time that you think, you'll realise this was a good thing for you, because she gave you the chance to meet a better girl
Not gonna happen you say? I bet you'll be laughing at this episode before they release Windows Vista SP1! Give yourself a chance, you really deserve it.
hope this helps.