My 2006 impala won't shift out of park and brake are weak going to the floor

As far as the not shifting out of park, there is a lockout sensor for the sifter and a brake positioning sensor. So when you step on the brakes the system will unlock the sifter. A-lot of times there is a wire that breaks at the sensor for the sifter. For the brake pedal going to the floor, I suspect a leak in the system. Need to check the brake fluid and if it low, down to the bottom the ABS system may need to be bled out with a computer program, you cannot manually bleed the ABS unit. You may have to have the car towed to a shop if you cannot get it out of park, I would suggest having a professional look at the brakes at least.