Help, Please......Casio WK-3000 and Garageband problem

Ok, i Have a mac book with leopard on it, not sure exactly the deatails of how advanced my mac is, but i no it a macbook with leopard.

But heres the problem....

I have a casio Wk-3000, and i want to connect to to garrage band so i can use it to play the beats and tunes garage bands has to offer, the midis to be exact, i have a midi usb cord, that came with the casio 5 years ago when i got it. But when i connect it to the comptuter it does not make any sign that it is hooked to my computer, i read that macs are not compatible with casios, but i also read despite that there is a way to at least use the keybord to play the midis and the garrage band sounds and make music with the computer features.

I need help, is it possible to connect my keybord to garrage band in any way shape or form, even if the casios features, and pointless.

Thanks