As somebody who spent far too much making his first feature can I just ask a few questions by way of advice.
1) Have you got distribution for the film?
If the answer is no, in real business terms you are looking at a $177,000 investment into a product with no return value. (Asuming that "if you make a good enough film it will sell" is dangerous thinking).
If the answer is that you do have distribution then raising the investment shouldn't be that hard.
2) Could the film be made for the moeny you have, if you gave up the need to work on film?
Again this is a straight business question. If the film is sales worthy then it isn't going to make a difference to it's market value whether you shoot it on film or HD. In terms of cinematic integrity, I can in all honesty say that HD holds up beautifully when shown in cinemas and only a real geek would be able to tell the difference. Your average theatre goer won't know or care.
HD has the added advantage of being a faster production tool, and when it comes to production budgets taking a week to ten days off your shoot make massive savings. It can also be a lot cheaper in post, depending on how you do it.
What I suggesting you do is stop looking at your film as a work of art and start seeing it as a product. You need to have a realistic understanding of it's market value and from that you can figure out whether it's worth the additional investment.
The other thing is that I suggest that you step back a litle from your artistic integrity and ask yourself whether you aren't just being narrow minded as to your production tools.
Personally with your budget, I'd shoot the whole thing on DVCPro50 (SD) and after the online knock the whole thing up to HD. No one will be able to tell teh difference, it'll transfer to film beautifully and you'll have a better margin on your first feature that will bring investment in on your second.
