If you are really desperate, do what I do...
sound recorder in accessories
you just gotta get the volume right
if there is a chord connecting your two comp. speakers together you can take that and attach one end to the keyboards Phones/output with an adapter, and the other to the audio in thingy on the back of the comp.
You'd need an adapter though...
or you could get a USB cable and hook it to the keyboard...I dont know how yet though.