If you have two unused pins available, you could use them to run a Pololu stepper driver. Of course, you would also have to be able to recompile the firmware for your mainboard.
Alternatively, you could rework stepper driver on your mainboard. Without a rework station, removing the fried chip can be challenging - I've had success by carefully cutting the pins with a dremel tool, but carefully is the active word here - it's way too easy to damage the mainboard.
