Depends on what kind of chiller you want. I'd suggest a standard immersion chiller. If you are looking for a ballin price you should hang out in the classified section for a few weeks and swoop one up there, craigslist is another option. If you are less patient you can just go to midwest supply, austinhomebrew, northern brewer, or your LHBS and find them all for around the same price. Should cost around 100-115 bucks for a 50ft chiller. Copper or stainless both work fine, I have a copper chiller for my chiller and a stainless for my herms coil, both 50ft. I think if I had to do it again I'd go with a stainless chiller as well cause it doesn't tarnish and I am picky like that. The performance difference will be undecernable.
As for the regulator I don't have a clue. GL with the equipment.