Is this subabru a floor shift? I imagine it is. There should be a small removable access panel just bigger than a key next to the shifter, pop out the small peice of plastic and theres a button in there, use a key or screwdriver and push in the button while trying to shift out of park. It should release the shifter.

Ensure brake lights are working when brake pedal is depressed. If lights are working and you do not hear a clicking noise at gear shifter, the interlock solenoid is not working.

If brake lights are not working, check the fuses. Releasing the shifter manually is for temporary use and you need to have the brake lights working.