I lost my public key! :(

[trena]

Hello,

According to my understanding of how PGP works, I should be able to get
out of this mess, but I'm not quite sure how to go about doing so with
GPG. Here's a summary of my scenario...

I use GPG to encrypt a "filesystem in a file" that I mount using the
loopback device, and keep my secret key on removable media. My .gnupg
directory has a link to the secring.gpg file on a floppy, and my public
key was kept on my hard drive. Thus I only need the floppy when
unencrypting the filesystem, and could re-encrypt it using my public key.

Unfortunately, I wiped my hard drive and installed a new version of
GNU/Linux on my laptop and did not back up my public key (I mistakenly
assumed all my keys were on the removable media).

I have the secret key and my passphrase. Now how do I unencrypt the
filesystem? I tried re-creating my keys and replacing the secret key with
my old version from the floppy, but that doesn't work because the key IDs
don't match. Can I edit the ID somehow in the new public key so it will
work? Other ideas?

Many, many thanks,

Stu