Accidentally "undid" a file copy, but files not in trash & originals gone

Help! I accidentally "deleted" some files by undoing the copy action, but when I tried "redoing" to copy, the computer wouldn't do it. Now I can't find the copied files and I've deleted some of the originals.

I copied a bunch of video and photo files from my video camera to my laptop. I then ejected & disconnected the camera and started deleteing files from it, but stopped a couple of files into it, intending to make sure they'd copied to my hard drive OK. I went back to my laptop, saw them, and thought all was OK. For some unrelated thing, I thought I needed to undo some Finder action, so I hit command-z. To my surpise, this removed the 500MB of files I'd just copied from the camera. When I hit command-shift-Z to restore my files, I met the message that this was not possible since the original drive wasn't there. My files are no longer listed in the Finder window and there are no actions to Redo or Undo.

So my files are there somewhere because they were never really deleted. But they were never sent to the trash, either, so they aren't there. I opened an X11 window in a vain hope I might find them, but that was fruitless. All my searches for recovering lost files yield results that pertain only to getting files out of the Trash or recovering them from emtpied trash.

What can I do? If someone has a unix/Darwin fix for my problem, I'm all ears.

Thanks.