If this is the case, its PROBABLY which ever you get to first. If you hit 12k miles before the 12 months, then its expired. Otherwise once you hit the 12 months the warranty is over.
Im doing my own headgasket fairly soon, but I plan on having the head resurfaced and getting new head bolts (along with new valve seals and guides for the valvetrain). What rockadilla probably did was just take the head off and put a new gasket on there. That is not the best method, because you cant eyeball any warpage on the head, and from what I have come to understand, you DO NOT want to re-use your headbolts.
You can probably take the car to a performance/machine shop and have them put a helicoil in the stripped hole. I cant see that costing more than 50 dollars, but I dont have any first hand experience with helicoils.