To expand on this:

The folder drive0/fids contains all the MP3 files. You can simply copy all files ending in "0" and you have retrieved your MP3s.

If you want those files ORGANIZED, then you would have to have properly tagged the files before sending them to the player in the first place, a tip I keep repeating to everyone over and over again. If you did that, then you simply need to use a tool like MP3 Tag Studio to organize the files into a tree structure and you're all set.

If you didn't properly tag the files before sending them to the player, then you have no easy way of knowing which files are which without either examining the *1 files or listening to the songs.