Odd that you only have three screws - my '05 has four - two on the top edge, one on the lower indie edge (deeper in) and another on the lower outside corner - this last one is the swine to get at.
Here's an image of the cover - this is the left side - view is from the front, looking back.
The swine screw is the one on the lower right in the above image (lower left side on the car)....