Brakes Failed problems of the 2008 Toyota Avalon

I purchased a used 2008 Toyota Avalon limited from hornburg Jaguar dealer in santa monica on 10/29/2009. At home at 8 am, on the clear, cool day of 11/1/2009 I had the car parked in my driveway to install the garage door opener. Wanting to move the car to the street I started the car using the required proceedure for a pushbutton ignition (like on my 2007 Toyota camry hybrid for 2 1/2 years). That is, I stepped on the brake and pushed the ignition button simultaeneously. The car started to move rapidly down my short sloping driveway (7 or 8 feet). As I pushed harder, the break pedal in effect went to the floor- no breaking at all. I hit the curb very hard on the other side of the narrow street, the rear end of the car bouncing into the air , and ended up, perhaps 10 feet beyond, hitting the front bedroom wall of my neighbor's home with considerable force and resulting in significant damage to the wall. I apparently did not sustain physical damage. I am inclined to believe there was an accelerator component problem also because I was moving so fast. The car is being repaired now physically, as is the house, and I have contacted Toyota locally in torrance and I understand someone there will follow-up on this accident within the next 4 days. I tried to duplicate the brake failure problem with my camry hybrid and I was not able to duplicate it. When pressing on the start button and the brake at the same time I always have a firm brake on the camry. When I duplicated the proceedure on the Avalon I found that the brake pedal went soft rapidly, the more I pushed it, to the floor. My repair shop will not drive the car until something is resolved, nor will I. I will be glad to furnish anything more you may wish to know about this incident.