Just my .02 - I'd switch to vBulletin or something like that. They've got plenty of great plugins and such, and its a one time fee! No monthly bullshit.
As for this forum, I'd leave it up just to piss them off. You paid for a license you have the right to use it - they won't do anything about it.
As for a new forum, change it to osxlatitude.com/forums/ and swap everything over there. In the meantime keep this here for data and whatnot till the accounts and such can get swapped over.