i think the rotor needs to be polished.by the passage of time and sumtimes due to frequent heavy braking, the rotor( the shiny disc type thing) gets small ridges in it which changes the surface which has to come in contact with the pads, this causes abrupt braking, shaking steering wheel and noise when braking.
take ur car to a good mechanic, get the rotors checked, if the problem is as above, the mechanic can polish the rotor but if its in toooo bad condition, u ll have to get new one.