Restore from system image which has been moved to external HDD

Hey guys.
So here's what I've done so far:

Bought new 2TB HDD for my early 2009 iMac 24", installed it. put old HDD in an enclosure.
Used SuperDuper to transfer OSX partition without a hitch.
Used Bootcamp Assistant to create new 1TB partition for Win7 pro 64 bit. Formatted to NTFS with win7 install disc.
Tried to use winclone to image and clone old Win partition, failed.
Banged head against the wall for a bit.
Recovered
Opened up iMac's guts again and swapped the drives, used win7 backup and restore to image the windows partition onto the 1TB empty partition on new drive.
More open-heart surgery, swapped drives back so 2TB is in iMac, 640GB is in USB enclosure.
Deleted original Win7 from 640GB drive (worrying but I didn't have anywhere else to put the image)
Copied image from 2TB drive onto 640, also made a copy of it in my Mac HD (using Paragon NTFStools to enable the copy)
Booted from Win7 DVD and tried to restore from 640 to 2TB. failed.
Cried for a bit.
Deleted everything on new HD's NTFS partition.
Tried the restore again, still failed: recovery to the backup storage location is not allowed.
Checked that the location of the backup was the correct drive (E:)
Sacrificed a goat.
Tired repartitioning, reformatting etc. the 2tb drive.
Read the whole Internet.
Cried some more.
Registered here.

So I understand that system restore wants to restore TO the drive that it originally took the image from, which is where the image now is. This is all fine and lovely, but I want it to restore FROM there, TO the new drive, and I just can't find a way to do it. I currently have reinstalled win 7 onto the bootcamp partition of the new drive, as I understand I can possibly manually extract the most important parts of my data, but I thought I'd ask you guys if there was another way before I set about using the next 3 months' bandwidth reinstalling and updating everything, not to mention the fun I had trying to force new NVidia drivers to play nicely with my mac under windows.

I do have another HDD which I could theoretically back up, wipe, format and save an image to, but this would first require me to switch the HDD out of my computer again, copy the image onto the new big drive, enclose the third drive, copy all its data onto the big drive, then swap the HDD AGAIN to restore the image to the old system drive, swap enclosures, back up a new image onto the third drive, then swap HDDs again so I could restore the new image to the new HDD. And tbh, just typing that has made me very unhappy.

So if any of you wonderful peoe can think of a simpler way to get the image off the 640GB drive onto the partition I set aside for it on the 2TB drive, you will have saved the rest of my weekend and I will be insanely grateful, and may just possibly not go on the rampage with a shotgun.

Edit: Also, I have made sure that the image folder is in the root directory of the 640 drive. There's nothing else on that drive. Or on that partition, anyway. The drive still has an OSX partition on there with my original OSX installation untouched