You can get MGW shifters at MGW Mustang Shifters
(Stangmods) you will probably have to call them for the 2011-2012 Mustangs. They are not on the website. It is probably just as easy to call MGW and get on the list. I'm paying $411 for mine, but I'm also getting the heat shield. I'm on the list and was told mine will ship late this month.
Go to the link below to follow installs of the MGW Shifter, I believe that gregtommy is working on a step by step install sheet based on his recent install.
MGW Short Throw Shifter