Email your host lol... Their the best shot.
I am hosted at
www.hostnuke.com which provides me with a plan of 10gigs HD space and 50gigs monthly bandwidth. They have just about any feature that you could want, and, if their lacking something that you need, there is always the possibility to ask about getting something added to suit your needs.
If the site has say 3000 board members, it'll have approximately (an educated guess) a 10 gig bandwidth need. Most UBB's will need 50 megs of space for growth.
www.hostnuke.com offers some 10gig bw/150meg space plans for like $9 a month, the servers are quite nice, just tell the admin that Gizmo from UGN sent you and theil be nice
...