I think that every teenage kid just wants to be "normal". It is especially hard for teenagers to have an illness like bipolar disorder that has such a stigma. I think that eventually your daughter will get sick of her life falling apart, and realize that she needs the meds. Maybe it would be a good thing for her to live with her Dad. That way when things happen she can't blame you. And she might realize that there is more to her problems than just dealing with you. If things go really bad with her dad then she could always come back. That way at least you both would know that that situation is not any better.
I might also try a little harder to see if she could be hospitalized. At 15 I think that you could sign her in, and she wouldn't have any control over it. You might want to talk to her doctor and see if he/she could pull any strings to get her in. I think once she is in the hospital that they can force meds if they think she is a danger to herself or others.
When I'm not in my right mind, my left mind gets pretty crowded...********************