Go to http://www.prestone.com/
and look in the upper right hand corner. You'll see the yellow bottle that says "all makes/all models". Then, it depends on which you buy...the one already at the 50/50 mix, or the full strength. When you flush the system, you'll have roughly half of the capacity of the system filled with water within the engine, so it would be best to fill the radiator with the full concentration.
Some have had luck cleaning the overflow tank with a rag and brake cleaner. It can be hard to get in the corners, so I also use a rag, a few marbles, and a good liquid cleaner to finish it up.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.