2004 Lexus ES330 brakes problems

I drove off the highway , route 50, in annapolis, md, onto an exit ramp leading to ferguson road. I applied the brakes but the car did not slow down. I avoided a car on the ramp in front of me but immediately came to the stop sign at ferguson road. The car had not slowed down and I attempted to make the left turn onto ferguson road, but hit the guard rail and another car in the intersection. The air bags did not deploy.

When braking and slowly turning left to come to a stop in a parking space at a wal-mart parking lot my car suddenly accelerated uncontrollably at such a fast speed that my car crashed into a metal pole and pushed a parked station wagon facing my car back far into another isle. My foot was definitely braking the whole time.!!!! My car unexpectedly accelerated at a very high speed while I pressed the brake. I have in my possession a surveillance tape of the accident taken by wal-mart.