Sorry if I am wrong, but I dont know of any unformat utility that will revert you back to the way it was before a format. I know there are tools available that will help you recover lost data after a format for example EasyRecovery. You can use this on an ext3 file system. After you recover what you want, just reformat as fat32 again and then copy back.
I reserve the right to be wrong, but if there was such an animal I would have used it a few times.
Hope that helps.
What commands are you talking about in dos? I still play with that all the time so I would be interested in this.