S.D.
We're a family of 4 hungry fish/vegetarians. We spend ~$200/ week. We get diapers at Target, which for us is cheaper than the grocery store; wet wipes at Costco. Our veggies come from a CSA ~$120/mos - basically an arrangement with an organic farm like Terra Firma Farms - before this, we used to shop at Trader Joes and the farmers market. Most of our fish comes from Costco. Costco has organic milk and coffee as well as great meat (so I've heard from my very carnivorous Father in Law), but then, ours is 5 minutes away...
BTW - Average food bill of $160/week probably is not in the bay area or organic.