I have a few contingency plans:
There are details I could disclose, but I don't want others stealing my resources. But my plan does involve armored vehicles in which I have access to. But as Austin said, I basically plan on setting up a defensive like position and staying put. As long as all my resources are in tact, I will have no reason to venture outward. At that point, it's all about me.
Currency on one hand, could be anything from a can of soup, a pistol, water, gold, etc...
I believe a trading system like one from the old west would be adopted.
Virus/Biological outbreak, I have covered thanks to a J-LIST and Pro Mask with a few filters.
And I'll have my arsenal complete by 2010, to include a larger stand off weapon.