I'd like to pick this game up with whatever expansions are available but I can't find it for sale online. I can't navigate the publisher's Japanese language website and http://japonbrand.ocnk.net/ lists it as "Sold Out"
they told me they won't have the expansion in stock again until October 2011 so I didn't pursue the matter any further
The expansion is completely redundant. It's only if you play the game to pieces. The expansion is hysterical, next to game-breaking and you need both players to be very aware of what you're doing before you start using it.