Clear out a section of ground around the base of the rock on the opposite side of the direction in which you need the rock to move.
Place the block of wood next to the cleared section of ground by the rock. Push the pry-bar under the rock and over the wooden block, making sure to push the bar as far under the rock as possible.
Reach up to the top end of the pry-bar and pull down as hard as possible. This pushes the bottom of the pry-bar up, forcing the rock to roll up and away from the pry-bar.
Repeat this process until the rock is moved as far as needed.