You don't have to buy a replacement vent piece. I had the same issue that I fixed five years ago and it is still in place. Just fix it yourself.
Carefully pry up the vent the rest of the way and remove it from the dash. Don't forget to unplug the light sensor on the dash. Use a heat gun or even a hair drier on hi heat and aim it at the vent clips on the underside of the piece. Don't hold it there too long, just enough to soften the plastic clips a little. Once the clips are hot, carefully push them using a screw driver just slightly and hold them until they cool. You can also move each of them about 1/8" out and then spray the clips with cool water to "freeze" them in place.
Then just dry it, plug in the sensor and reinstall. You will know if you moved the clip enough if the vent stays in place and doesn't pop up again.
Good luck.
Ted
