Quickest, easiest and possibly even cheapest solution (if you can return the head gasket and bolts): Replace the entire engine with a good used one, which you should be able to pick up for a few hundred $. Used engines are not hard to find. If you can hear the engine run, do a compression test, and see that the oil and water are not mixing, you can be fairly sure that it will work properly once you have installed it. If you try to fix the engine you have, assuming the pistons are stuck in the cylinders with rust, you will have no end of trouble.