Simon
You can buy what you need from Andrews:
http://www.andrewscom.com.au/site-section-10.htm
It's best to give them a call and they will make sure you get the right stuff for your combination of scope and camera.
The adaptor to link your camera to the mount is quite cheap, so it's a good way to get started with some unguided prime focus pics of the moon or short exposure stuff.
If you get hooked and want to improve your images then you will need to spend some more $$ and perhaps get a new EQ style mount for the 8i instead of a wedge - and keep the Nexstar 8i mount for visual stuff.
Why don't you also look into putting the camera on the C10? It has an EQ mount with tracking already right?
James