AFAIK for any of the download versions of the game the patch needs to come from the same distributor as the game.
Did you check for updates from the game's start menu folder? It may already be at the latest version. In any case, there was only a hotfix released for the US PC version to fix a problem some people had crashing when shutting down the game, so you may not need it even with the original US release.
When the next patch is released (expected about the same time as the add-on, this 'summer'), you will likely need to go though EB Games to get the update (they have to package it so it conforms to their distribution and DRM system).
