You can't find them because they're hidden. I'm not positive about this, but i'm guessing those files were autosave files perhaps...and they automatically delete when you close the application. Are you sure you don't have your original files stored on the computer somewhere? Did you try searching for the original files?
If you really need to recover the deleted files, you'll have to turn on hidden files. You'll need software to do this (there are probably other methods, but this is the one I use). Google a program called "OnyX". It's a utility for OS X. In there, you'll find a setting which allows you to show hidden and system files on your computer. Once that is done, you should be able to browse to the files and get them out of there. You may need to do something to them, to prevent them from being hidden once you disable "Show hidden and system files" in OnyX. Not sure how that is done though. Maybe changing the permission of the file or perhaps there is an option to disable "hidden". Select the file and then hit Apple + I to bring up the info properties panel for the file. Look for settings which may relate to what I just said.
