It looks like The 2012 United States Silver Proof Set, The 2012 United States [Clad] Proof Set and The 2012 United States Mint Presidential $1 Coin Proof Set have sold out. These proof sets are now being listed as "Sold Out" on the U.S. Mint's website. There are still several other 2012 proof products that are still available for sale. But don't despair; a quick check of the Internet and a call to my local coin dealers has revealed that there is still an adequate supply of 2012 proof sets that are available for purchase. Of course coin dealers need to make a living, so these sets sell for a small premium over the original mint's purchase price.
The 2013 proof sets will be going on sale early this year. According to the mint's product schedule, the 2013 United States Mint Proof Set will be going on sale on March 28, 2013 for a price of $31.95. The mint will start taking orders for the 2013 United States Mint Silver Proof Set sometime in May at an initial price of $67.95.
Image courtesy of: The United States Mint