2003 SUBARU WRX Power Trainautomatic Transmission Problems

I HAVE A 2003 SUBARU IMPREZA WRX STATION WAGON WITH AN AUTOMATIC TRANSMISSION. THE INCIDENT ON JANUARY 19, 2004 IS ONLY ONE OF AT LEAST FIVE EXAMPLES OF THE PROBLEM DETAILED BELOW. *AK HERE IS THE RECURRING PROBLEM: WHENEVER I BRAKE AT RELATIVELY LOW SPEEDS (UNDER 30MPH AS FAR AS I REMEMBER) OVER EVEN MILDLY BUMPY SURFACES, THE BRAKE PEDAL DEPRESSES COMPLETELY TO THE FLOOR AND THE CAR DOES NOT BRAKE. THE CAR WILL NOT BEGIN BRAKING UNTIL I REALIZE WHAT IS GOING ON, RELEASE THE BRAKE PEDAL, AND THEN HEAVILY DEPRESS THE BRAKE PEDAL AGAIN. I ALMOST HIT ANOTHER CAR BECAUSE OF THIS ISSUE ON JANUARY 19, 2004. THIS IS VERY BAD, BUT EVEN WORSE IS WHAT HAS HAPPENED IN THE PAST -- I LIVE IN SOUTHERN CALIFORNIA AND SOME OF THE PEDESTRIAN CROSSWALKS IN MY AREA UTILIZE RAISED, WHITE-PAINTED CONCRETE SURFACES TO HIGHLIGHT THE CROSSWALK. THIS RAISED, UNEVEN...