You can get both CD-4 and HAS from Artcraft Chemical or Photographer's Formulary. If you want to mix developers and things they are your friend.

I'd also suggest you make up your chemistry 1 litre at a time unless you are planing to use it one shot. Even so, for a first attempt you may find yourself tweaking it a bit. Color chemistry doesn't last all that long. A few weeks maybe but not months.

Lastly, you will need to add sulfite to your stop bath, or you will get horrible stain on your negatives. The amount to add is in the forums here somewhere. However, you can go overboard and it won't hurt so too much is better than too little. Search under C-41, or ECN-2 maybe. Anyway, the sulfite scavenges any remaining color developer before your bleach step. Without the sulfite any developer remaining in the emulsion will "activate" all the color couplers forming dyes for all the colors that will essentially put a dark brown mask over your negatives. That's a very simplfied explanation but essentially what happens.

Note that stop bath doesn't remove developer, just deactivates it by changing the process to an acid pH instead of alkaline. Developer has to be washed out of the emulsion.

Have fun!

-- Jason