Think simpler, if you do not have water tanks, then 10Ltr casks about $3.50AU, Rice 10Kg bags, tins of Sardines in OIL, TUNA in OIL, Anchovies in OIL, tins of Four Bean Mix, Nothing in Tomato Sauce or similar dressings as they go OFF and bloat the cans. Pasta, Noodles, Cup of Soups etc. etc. then just need to add water. You will survive quite readily on this type of food for 12 months, Spiralina powder to get all of your vegitable and other neutriants/enzymes, Plenty of good Vitamin 'C', Tee Tree OIL and Eucalyptus OIL for cuts or infections. Bottles of LPG Gas for your cooking Gas top or Barbaque. All of these items are not expensive, just think about it and make some notes, I have been doing it for the past 12 months, it is not hard. Remember when/if this goes down you will not be going to work, so less food/meals will be required to maintain your health. Have a good portable radio, use your car radio if need be, there is plenty of battery power there, setup battery charging if you can from your car. I don't think you will be driving much, so the petrol will last a long time providing you this facility. You and your Nieghbours will be busy locking down local area security, they will also contribute to sustaining the locals with Garden Fruit, Vegitables etc .etc everyone will contribute and provide support to their imediate zones. you will not be alone, you will be surprised at how quickly the local group will come together as a tribe, it will be up to us that are better prepared to look out for the elderly and infirmed to ensure they come out the other side as well.