Changing Interests After Getting Accepted for PhD I have brought some trouble onto myself I know, but what can be done by someone in my situation.

I applied and got accepted for a PhD program in Computer Science.  I automatically assumed that I wanted to continue the work I did on my Master's thesis and I identified a professor who would be willing to work with me on that subject.  When I got there, I reviewed the literature (there had been a few years of gap since defending my thesis) and decided I really did not like the direction the field was going in.  I had been developing a new interest anyway, so I changed sub-disciplines.  Now, no one will commit to be my advisor, at best maybe co-advisor with some outside expert.  Part of the reason is because my school lacks experts in that area.  I personally (on a friend basis) know some Computer Science professors, but none are experts in my field.  What can I do?  No advisor = No PhD, I know that much anyway.
Changing a subject during the PHD course is legitimate, and not very rare. However, finding an advisor is a must. I think in that case you'll have no choice but trying to convince professors to be your advisors. 

A possible way is to find an expert from a different university, that will be your co-advisor. That way you'll just need to find another faculty in your university that is not-too-far from your interests. You might find someone that will tentativly be your advisor, and once you show some progress will agree to take you under..

But maybe the big question is,
why not moving to the place where the "experts" are?