OK, Do you want a Jeep NOW, or are you willing to wait for more power and better mpg?
There's no guarantee the 2012 is going to be a huge leap forward, but the numbers are looking good. Understand that while the new engine and trans are already in use in other models, it does not guarantee that there won't be issues with them in the Wrangler. But, you could also have problems with a 2011.
Assuming it's still offered, you can use the Tread Lightly discount (do a search) on your 2012, to guarantee 1% under invoice. This will also work on the 2011.
We can't tell you what to do, that's your decision. If it was me, I'd hold out for the 2012.