Some dude e-mailed the PR guy of GSC games and asked about upcoming patches. PR dude responded and said that they were indeed working on a new patch. No details, though he did say that they were working on optimizing the game even more. No ETA as of yet.
Also, this patch would not be compatible with old savegames, just like the first patch. However, they're supposedly working on a tool that will convert the savegames to the new gameversion so people won't have to start over. They said they would release this tool around the time of the new patch.