I guess i need to know just a little more, is the entire system going to be 12 volt? If so, you can buy an alternator with a built in regulator, then you can loose the one in your drawing. But, if you are going to use a 12 volt generator, then you would need a 12 volt voltage regulator.
Honestly, the best thing to do is buy a wiring set up like this one:
http://www.speedwaymotors.com/Speedway-Economy-12-Circuit-Wiring-Harness,2352.html This set up is only $145.00 and has everything you need to do a complete wiring job without any hiccups. They even have the wiring diagrams:
http://static.speedwaymotors.com/pdf/910-64017.pdf If you really want to buy all the wire you need, and all the extra parts, just follow one of their diagrams for your set up.