USB3 wont bottleneck a HDD in terms of raw bandwidth, though it will still be outperformed by a SATA interface. USB on the software/driver end is more oriented to random read/writes while SATA is much more Sequential.
The drive is already failing, so I wouldnt trust it too hold anything you want to keep. Even if its not spinning during the time that's no guarantee it will work when you plug it in in 6months. I would back up your pictures either to another external drive or CD/DVD's.
Okays, ill try to figure something out then, thanks for all the replies!