I have been looking online to answer your question. Smuckers makes a dulce de leche caramel sauce. It can be purchased online at www.smuckers.com, and it might be found in the larger grocery stores, possibly in the ethnic food section.
Also, I would imagine that Mexican markets in OC would have it.
Here are a couple of supermarkets that might carry a brand or two of dulce de leche in OC:
Northgate González Supermarket
722 N. Anaheim Blvd.
650 North Euclid St.
Anaheim, CA 92801
Good luck, and please post if you find what you are looking for. :)
Northgate definitely has it -- I've bought it there when I was too rushed to make my own. We bought it at the one on Lincoln and... uh... damn, it's near Harbor, and I've seen it in the one on East near the 91 and the one on Euclid near Ball.
I imagine Gigante would carry it, and I'm sure Fiesta Mexicana would as well.
Some of the more "ghetto" Stater Bros. have it -- the one on State College and La Palma has it, but the one on Tustin and Katella doesn't.
(For those looking in LA, any of the big chain Mexican markets will have it -- Vallarta, Superior, El Super, etc.)