I'm not aware of any way to get a copy of the operating system/software image for the SMS3.
If your drive is still functional enough to make a copy, you should be able to use it as a master to duplicate to a new drive using a hardware based IDE drive copying device.
These devices create a bit-for-bit copy and are operating system independant so should work. You might call around to some PC repair shops to see if they have one.
I'm not aware of anyone that's been successful using a PC and copy/image software to do this. The SMS3 is Unix based, so maybe someone with Unix disk imaging experience could help?
Please let us know if you have any success...