What lens is best for taking pictures of the moon with my Nikon D5100?

The super moon is June 23rd and I want a new lens for my Nikon D5100 I got for Christmas. I only have the standard 18-55mm lens that came with it. Any help would be appreciated!

As an absolute minimum, 350mm focal length. 500mm or longer would be better. And a very solid tripod. Start saving your pennies.

Get a solid tripod and rent a lens. Here is an inexpensive rental:
http://www.lensrentals.com/rent/nikon/lenses/supertelephoto/tamron-200-500mm-f5-6.3-sp-di-ld-for-nikon

The site has plenty of other options that are going to be brighter and/or better optically, but they are more money.

In order to keep the moon sharp in the frame as the Earth rotates, you need to shoot no slower than 30/focal length, so at 500mm, that is 1/15th or so.