Sorry for the late answer.
1) Firstly, perform a low level cloning of your external hard drive to another external hard drive.
2) Secondly, unplug your original external hard drive (so that your HFS+ data won't be damaged).
And keep it as a backup during all the file recovery.
3) Thirdly, plug a third external hard drive where the extracted files will be outputted.
4) Lastly, use a good data recovery software to recover files from FAT/NTFS from the cloned hard drive.
For any other query about this utility, visit: http://www.windowsrecovery.recoverdatatools.com