Grated Fresh Coconut
Vietnamese, Thai or Filipino grocery stores will sometimes carry frozen pre-grated coconut. This way, you can keep it in the freezer until you need it. I've used it make fresh coconut milk (defrost, add hot water and strain out the solids) for curries and to make coconut roti (recipe called for half flour and half fresh grated coconut).
Not in Pasadena but relatively close by is India Sweets and Spices on Los Feliz. You might try asking them as well.
Whole Foods has fresh coconut already cut into chunks and sold in the cold case w/other cut-up fruit. If you buy, check for freshness. Sometimes it's ick. How to tell: brownish, slimy and smells funky. Easier than cracking open a whole one tho. I also buy and prefer, Organic Unsweetened Coconut flakes sold in a green bag and bought at Sprouts. (where the Gluten Free products are found). You have one on Rosemead Blvd 626.696.1290. I keep the unused in the freezer. :)