CHKDSK Finds Unrecoverable errors

Running Windows XP pro on an Alienware desktop. There are two seperate HDDs in this machine, i.e. C and D. The system disk is fine, but the disk used for the majority of data storage and on which the "user" directories were stored is apparently damaged. ChKDSK finds several unreadable blocks, then stops running during recovery, returning this message, "Volume appears to contain one or more unrecoverable problems".

I plan on purchasing a new HDD as a replacement. I would also like recover as much of the data on this disk as possible. Is there any software that will transfer data from this disk? Perhaps there is software that can repair the drive enough that it will run and let me do a quick back up to capture as much data as possible?

Thanks in advance, this forum is truly invaluable.