Place a ruler next to the toggle bolt's head, horizontal on the wall. Center the head at the 1 1/2 inch mark. Place a mark on the wall at the top of the ruler and at the 3 inch mark. Turn the ruler to run parallel next to the toggle bolt's head. Center the head at the 1 1/2 inch mark and place a mark on the wall at the 0 inch mark and at the 3 inch mark.
Draw a square around the toggle bolt's head using the marks you just made. The toggle bolt's head should be centered in the square.
Push the tip of a drywall saw through one of the square's corners. Push and pull the saw in a sawing motion to cut through the drywall, following the lines you made. Cut the entire square out of the drywall. Hold onto the square while you cut along the last line so it does not fall behind the wall.
Grasp the toggle bolt's wings with a pair of pliers and use a Phillips screwdriver to remove the bolt. Place a drywall patch on the square you cut out and follow the manufacturer's directions to repair the hole.