The expansion will come with the PS3 release. They already have the PS3 version ready but they are holding it back for obvious reasons. Once the core of the game is fixed we should start seeing things progress at a much more rapid rate as content that was pulled at release will be adjusted and put back in along with new content. Maybe however they may just save as much content they have ready as possible and combine it with the expansion to make it huge to generate even more hype for the PS3 launch.