This is some stuff I found:
The brake transmission shift interlock (BTSI) system prevents the automatic transmission from being shifted out of PARK unless the brake pedal is depressed. When the brake pedal is depressed, the BTSI solenoid releases a lock paw. This enables the movement of the shift linkage and the operation of the shift lever.
When service operations are required, overriding the BTSI is possible. In order to override the BTSI, turn the ignition switch to OFF (not LOCK), and remove the TURN-B/U fuse (# XX) to remove the battery voltage to the solenoid.
Sorry to ask but with a car that has so many electronics as this, there is possibility of damage with jumping it. Is the car in a position that makes impossible to remove the battery and have it recharged at a local shop ? How many volts you have now at the battery ? Is it bellow 6 volts ?
You may have to use a device, is a cigarette lighter plug with a 9v battery that you plug in before removing the battery to save the ECM saved data, etc...