How do I plug my three prong dryer plug up when I have a four prong outlet?
You need a new dryer cord, not an adapter

What you need to do is remove the existing cord from the dryer (dryer cords attach to a terminal block on the dryer, typically accessible by removing a cover from the back panel) and attach a new, four-prong/four-wire dryer cord to the terminal block.  There is also a white wire running to the chassis ground screw on your dryer -- that wire needs to be moved from there to the neutral screw on the terminal block, thus disconnecting the neutral-ground bond on your dryer.