I reopened a dead single screen in 2003 in Iowa. The community really wanted it reopened and formed a 501c3 corporation which enabled them to apply for grants. They did so and secured a Main Street Iowa grant as well as a grant from the local gaming commission. This helped move the project forward to a point where I thought I could cover the rest of the expenses. The jury is still out on that one, though

In any case, there have been a few examples of community run theaters doing fundraisers in order to convert to digital cinema. Here is one near me
http://www.vintonpalace.org/digital.php
They seem to be getting close and that is roughly the same amount of money you were talking about. So, I guess I would advise you to start something similar with your theater and look for some donations.
Good luck and let us know how things progress
Welcome to the forum!