Seized brakes & now a bad knock '00 ml320

[seababe]

Greeting Master Benz dudes,

Seababe back with the 2000 ML320

So, I have been experiencing this brake dragging for a while, but only when I do alot of stop & go driving. Yesterday, it happened again & I made the fatal error of driving it the 3 miles home with the brakes dragging rather than stopping immediately like I usually do. There were no brake warning lights or anything, the engine temp raised a little bit, but no where near dangerous, the RPMs raised to between 2300 and 3000, which it normaly is about 1800-2200, so again I was not concerned & made it home for the usual cool down...except this time, I heard quite a disturbing knocking and a slight electrical smell. I let the engine cool & last night went to start her up to see if the cooling corrected the problem. The engine started right up, but the electric smell came back along with the knock, clacking noise. I had my wonder mechanic stop by to see what I have done to my car & he fears that I may have damaged a valve/hydraulic something or another. My closest dealer is about 100 miles away...any thoughts on what I have done & what it is going to cost me?? Whaaaaa!