Backup/archive without admin access?
 

Ok, so here is the situation.

There is a forum that some online friends and I have used for years, but the guy who set them up has disappeared. We're pretty sure it's only a matter of time before the hosting expires or some error kills the forum. Is there any way to create a backup of them without having admin access? I'd like to back them up, purchase a vBulletin license and restore the backup to a new site. Any help would be appreciated.