I'm not sure you can recover the files if you have copied them, but here are the steps to recover your files with the Linux Mint LiveDVD if you can no longer log into your system: viewtopic.php?f=18&t=134231#p720340
. Note that you must have your mount passphrase for this, which you would have gotten by running the command "ecryptfs-unwrap-passphrase" at any time after installing Linux Mint.
I'm guessing you don't have your mount passphrase, without which you can not decrypt your files
So your best bet then is to repair whatever is wrong with your system so that you can log in again. As WharfRat noted, we'd need some more info to help you with that. But if you have the mount passphrase, it's easy enough to recover the files with my other post.