oh wow... hehe you don't do a lot of mileage
if it was that long ago i doubt that they will cover it....
i reckon they missed something somehow... that should not have happened
well toyota never accepted the hg problem as a known issue, they have denied it since it was discovered so i doubt you will get recourse there
i say this time, do it yourself... stock gasket is fine... but if you do want to do the mhg route don't forget to get the head and block prepped for it as the finshes need to be mirror finish
i've done alot of 7mgte head gaskets and i know most of them personally and they're still running strong, never mind the thing breaking around it lol... like one was his tranny, another was his flexplate, starter motor, all sorts of random stuff haha
but yea... done to the exact same specs i noted before and they're still going strong
i would suggest doing a leakdown test and this will definitely tell you if your hg is leaking from cyl to water
gl