DiskWarrior built preview, but quits when backing up to external

My 1TB HD in my black Macbook just crashed and Disk Utility said that it could not repair it.

So I booted up DiskWarrior 4.4 and ran that. It was able to build a new directory with all my files, however it said "The new directory cannot replace the original because of a disk malfunction"

It went on to say that recovering my files from the Disk Warrior Preview is urgent and I must back up my data from the preview disk.

So I plugged my external into my Macbook and attempted to back up the files from the DiskWarrior Preview.

The first attempt, it was able to copy over 4.5GB (or a little more; I didn't see the exact amount) out of over 650GB of data before it just quit (the window that shows the preview and the external and that allows you to initiate the copying of the drive just closed out of the blue).

The second attempt backed up 5.7GB before it quit and the window just closed without warning. The first attempt may have backed up this much data as well. I don't know for sure since I wasn't looking when this happened.

Why doesn't DW tell you what happened? If I hadn't been there, I would not have known what happened.

Has anyone ever experienced this? What do I do? Is most of my HD toast and DW just can't handle it, or is there another strategy I can try?

I would be sick to lose MOST of my data, which accounts for years of work.