Export forum data

We have a Drupal 5.x site with a somewhat active community. The forums used to be hosted on phpBB, but was migrated to Drupal a few months back with the intent of customizing and further developing the site. Unfortunately our in-house software developer left before any work was done, and we're pretty much left with a site that uses the default theme and forum setup. The core of the site is the forums, and many users are unhappy with the Drupal implementation. We'd like to export the forum data so we can re-convert back to a 'traditional' forum system. Optimally, I'd like:

- Data to be exported in a format used by phpbb or simplemachines, preferably simplemachines
- Containers and forums structure to be exported to the above forum equivalent
- Users and passwords to exported
- Posts and attachments to exported

Stickies, polls, signatures, avatars, etc are not high priority.

I know that the forum module can be customized and extended, but ultimately would prefer to revert back to phpbb or simplemachines.

Thanks!