[livibetter]

sub-domain? did you mean add-on domain?

You just need to move (re-install) all bbPress files up a level. If you installed them into public_html/konpaforum.com/bbpress/, then mv public_html/konpaforum.com/bbpress/* public_html/konpaforum.com/

If you want to integrate into WordPress, then leave them and install WordPress in public_html/konpaforum.com/, would be a good idea.