Man I feel you there-- I have a 1993 impreza in south texas with all sorts of odd weather, rain one hour, 100 degree heat the next, and I SHREDDED the rotors due to the heat and driving style; but my impreza has 128000 miles on it (possible original rotors).
I have heard of certain european cars (new beetle) that have had the brakes give out as early as 3000 miles- and that's with clutch failure with the manual tranny. Those cars weren't made in europe though, but in mexico to cut labor costs, and to make more money. I sincerely hope that subaru is not doing that, because this 1993 subie is my first and I wish to keep with subaru for long time.
My opinion is to go to a "mom and pop" shop that is ASE certified and explain your predicament to them; I used to work for one and I have seen near every problem fixed that often the dealer indirectly causes. I am saying that the dealer IS AT FAULT and you should get a second or third opinion.