Will the expansion work with the version of TOME that i bought from GamersGate? What do i have to do to get it to do so if i buy the expansion here? Do i have to wait until the expansion comes out at GG?

The DLC?

Well i glanced at the package files for the DLC and it mostly gives you the new files in the game/addons folder, so it should work... A little manual work vs automated...Then enable it when you start the game.