You need a backup of the first 1MB of the drive to restore. I believe I have one lying around somewhere in the office, so won't be able to dig it out until tomorrow morning.
Assuming I have it, you need to restore it using DD, an application distributed with the DMS tools... and I'll help you get up and running with that.
Once you are back up and running, then first stop is running the hack so you don't run into this problem again!