Hi, check out testdisk and Photorec, by CGSecurity. FOSS, and available for most GNU/Linux distros.
I have had success with these recovering deleted files from a flash drive, and cd-roms.
http://www.cgsecurity.org/wiki/TestDisk
You have some reading to do, and you will need a partition equal to or larger than the partition you want to recover.
Check your package manager to see if it is provided by your distribution first.
Good Luck, regards Glenn