There is NO bonus content in the patch. The Xbox Expansion was always only for the Xbox, just like they announced beforehand. No announcements have been made for any new content for the PC version as of yet...
"Support for new maps" means just that... that when mod tools are released and you create new maps, the game will be able to recognize them. No new maps have yet been released though.
There are two patches officially (both are hosted on the official site LucasArts.com, as well as our fan file site LucasFiles.com). One is for domestic (US) and the other for international (the rest of the world).