Hey Steve,
The water pump is a Walbro, you can buy one at your local hobby shop or sites on line. It will come with installation instructions. You will have to remove the engine to get to the carb. Take the carb off and the intake manifold, you will see two vacuum ports. As per the instructions w/ the pump, you'll have to drill a hole in the bottom of the manifold at the vacuum port using a #29 drill bit and tap with an 8-32 for threads. Be sure to use Blue Thread Lock for the pressure fitting as well as everything you put back together. Don't want anything coming loose.
Check out
www.warehousehobbies.com for the water pump and the foam piece to hold the pump in place. I think you'll find the instructions very simple to follow.
Keep me informed with your progress.
Regards