You could keep looking on EBay, and here, for a used replacement keyboard. Or hook up a PS2 keyboard. Or use the USB keyboard as "drider" mentions. Instructions for doing this are at http://www.webplayer.0catch.com
However, all of these options has software inplications. Since you failed to say "what software" your machine is now running, it is hard to tell you how to support it. Even with that knowledge it would be difficult. I believe the keyboard has a built in mouse. So even if you replace the keyboard with a USB keyboard or PS2 keyboard, you will still need to add a Mouse somehow, to get back to the same functionality.
My advice is to keep looking on EBay, and here in the "Swap Meet" section, for an exact replacement. This will have zero impact to your software. You could even post a message there saying you are looking for one (I just checked, and I don't see that you posted a message there).