Okay, looking at the averages, with 45,000 page views per day and looking at a long month of 31 days, that's about 1,395,000 million page views per month. If you assume that each page has a megabyte of data to transfer, that's 1400 GB of data transfer per month.
I, too, host a forum for Arizona folks (Arizona HDTV Forums at
http://www.landlpcservices.com/phpBB2/index.php - always love new visitors), but I use godaddy.com for my hosting. Their premium hosting plan is $14.99 per month (less if you purchase longer periods in advance), and that plan allows 200 GB of storage and 2000 GB of data transfer per month. It allows 3 MS SQL databases and 50 MySQL databases. I use phpBB which uses a single MySQL database for all of the forums.
I'm not saying you should change to them, but in addition to looking for funding resources, consider asking your current host to take less money for their service.
All that said, I understand your plight, and frankly, even if it didn't cost you anything to provide this site, you're providing a valuable service. It seems that a more visible donation system and/or annual donation drives, even if they only represented profit, would not be unreasonable.
And to everyone else, while we're on the subject, I think I'll put my money where my mouth is. Follow me to the donation page, and how about donating what you think is fair today?