Sounds like a bad batery. There is a selenoid on the shifter assembly that electronically unlocks the shifter when the ignition is on and the brake pedal is depressed. It's not connected to the range selector on the transmission. One thing that I've noticed with these cars is when a battery is on it's way out all kinds of weird electrical stuff happens. Chances are that nothing is wrong other than the battery. The selenoid just wasn't getting enough juice after the headlights and brake lights sucked it all. The mechanical method is good to know in an emergency though. Basically all you need is a screw driver. On the passenger side of the console you'll notice a little slit. Just insert the screw driver until you feel the lever and just move it forward(if I remember correctly). At that point you will be able to move the shifter through all of the gears unless you put it back in park.
