If you have FExplorer or SeleQ, just go to where ever you installed the game (C or E), and go to System ->MIDlets and select the game. It will most likely show up as some number, so you'll have to check each one. Once you find it, copy the jar to where ever you want it, (as long as it's not in the system folder) and then pull it out with PC Suite.
If the app is installed on your MMC and you have a memory card reader, you can do this from your PC. Just make sure you check "show hidden files and folders" from the Folder Options in Windows Explorer.