While I'm not sure where the 405 (Freeway I'm assuming) enters into your preferred geographic area (?) I normally see these in the "olive bar" area at most Whole Foods Markets. So maybe checkout, (or call first to save yourself some time in case they don't have them) the one in Woodland Hills: http://wholefoodsmarket.com/storesbeta/woodlandhills/
ADD: Ah, epiphany. You meant from the 101/405 Interchange going west as far as Westlake most probably. In that case you might look for a Persian market along that stretch of Ventura Blvd. in case Whole Foods doesn't have them.
ADD No. 2: Here is a thread on Persian markets in the SFV that may well be of help in your quest: http://chowhound.chow.com/topics/47220