I, too, think you're out of luck for this file.
But for the next time...
But xl2k (and previous versions) does offer an autosave function--used it to
save your files at regular timed intervals.
As an alternative, you may want to consider using Jan Karel Pieterse's addin
called AutoSafe (note spelling).
It doesn't overwrite the existing workbook when it saves. It saves to a user
selectable folder. And when it's done, it either deletes these backups (or puts
them in the recycle bin). And the user can always restore the backups from the
recycle bin.
http://www.jkp-ads.com/Download.htm
(look for AutoSafe.zip, not autosafeVBE.zip, for your purposes.)