Restoring a partition on external hd

I recently upgraded my iMac to Leopard, and thought I'd make use of Time Machine. The program told me I'd have to back everything up on another drive, and since I have a LaCie 500GB hard drive I thought that would be plenty (my computer has about 150 GB internal memory). Time Machine told me I'd need to first erase everything before backing itself up, but I didn't want to lose over 3,000 high-quality music files, some of which are pretty rare.

I decided to partition the external instead. Unfortunately I didn't realize I wouldn't be able to access any of my music files any more. The problem is probably the filesystem type - the original volume was FAT and the two partitions were formatted as "Mac OS Extended (Journaled)". I KNOW the files are still there, but the original partition table data has been lost. How do I get that back?

PLEASE help, anyone! It's taken me a long time to get these files and I would hate to have to start over.

Does anyone have advice? I've already called upon a computer scientist I know and have emailed the company who made the hard drive for help, neither of which have gotten back to me yet.

I've tried both. For some reason, neither worked. I can't figure out why.

Edit: I should note that I've tried both a number of times using different settings. I've gotten nothing using either. I've demoed Boomerang, which is the ONLY one to tell me that the files are still there, but I've read that Boomerang is terrible software. It's the only one to see the files, though. I'm still going to try DRII and FileSalvage again, but I haven't had luck yet.

Second edit: The files I'm trying to recover are primarily .flac and .shn types. FileSalvage doesn't recognize those. Data Rescue II isn't programmed to recognise them, and the feature it has never worked well for me.

Of course not. That'd be way too easy, if I still had the CDs. The thing is, I got the music over the internet. Lots of jam band performances (perfectly legal, don't get any ideas). I can get the files again, it would just take a loooong time. It's much easier to restore the ol' HD to how I had it before. Stupid me didn't think to back everything up. That habit has changed already, and if I could get those files back I'll get to work on backing all of it up immediately.