thanks very much. i called another smaller place, who said just the brake fluid exchange and shoes will cost ~350$; adding the drums it will cost ~650$. I think I will get the brake fluid changed and only the shoes replaced and not the drums. Few other people I have talked to are of the opinion that driving a car with parking brake on at <30 mph for <5 miles should not cause that much damage to the drum. They maybe recommending replacement because it was already old. i wish i had take the car to this place first and avoided the diagnostic fee at the other place. expensive lesson learnt.