If you have another system, or have access to another system you can try this:
Seagate FreeAgent GoFlex USB 2.0 Cable (STAE100) : Interface Cards - Future Shop
Not sure if that link will work for you. It is a $15 cable at the Futureshop (webid 10148173) from Seagate for their Go Flex lineup (pn# STAE 100). You plug one end into the hard drive, the other into a computers USB port. If your drive is still readable then you should be able to get any data you want off it.
I have had a similair experience with two laptop hard drives recently. One was totally dead, and unreadable. The other only the OS was corrupted and I was able to pull data off it.
Either way its a cheap way to check, cause once your done you can take it back to the Futureshop. I am saying the Futureshop here as I don't have a decent pc store in reasonable driving distance from me right now.
Here is a link to the Seagate page:
Accessories | Seagate
The cable works with any sata drive, and as you can see on the second link Seagate mmakes the cable with USB 3.0, firewire and eSata ends.