The first one they show with the key on the body is the newer one. The second one is the one from 2010 which is sold out. You can get both on ebay, the current one for around $20 and the old one about $70.
The key figurine is currently available at Downtown Disney D-Street locations in Disneyland and Walt Disney World. No word on whether resort stores are also stocking this figure. A Disney Vacation Club member ID must be presented in order to purchase. Price is $14.95
The first one seemed to be around for 6-12 months. I'm not a big Vinylmation guy so I don't know what sort of production runs are typical. But these aren't individually numbered collectibles with a couple hundred total pieces.
Probably biggest risk is that you may have to go out of your way to find it. Sounds like resort gift shops are stocking them but the supply on hand may be limited. If your resort happens to be sold-out, then it may take more effort to track one down. D-Street is the location they are recommending.