Well, you can always download a GuitarPro tab. Here's a good one, it has the keyboard part: http://tabs.ultimate-guitar.com/d/deep_purple/smoke_on_the_water_ver6_guitar_pro.htm (Download button on the end of the page)
You can only view this file with GuitarPro or TuxGuitar software. I recommend TuxGuitar, it's a lot smaller and easier to use. Just open the file, select the "Rock organ" part and click play.