gHOSTLYFIGURES , that would be a Mini-USB plug, not firewire. It is one of the most common usb cables to be used nowadays. You should be able to get a replacement cable from any computer hardware store fairly easy.
For firmware extraction, you'll probably need S1clone v1.3 here
http://www.s1mp3.de/tools.s1clone.html
This software would be able to extract and as well flash the firmware back to the player. However, it has just been released and we are not sure if it would work fully for your player.
To theme your player, you'll need the new S1res v3.0 here
http://www.s1mp3.de/tools.s1res.html