well, assuming the car stops, then there's not a whole lot you can do in terms of trying to invoke the lemon law. i assume you're just driving "normally"? you don't ride your brakes or drive the car like you stole it kind of madness? how many miles on the car?
the metal-on-metal sound is actually normal (unless it's REALLY REALLY loud). this is dependent on the pad material. as far as the squealing, they should have placed some anti-squeal compound before installing the pads. i'm not sure what else to say. make sure the rotors are mounted flush to the hub and that you torque the wheels down properly with a torque wrench.