Sorry for taking so long to get back.
Here's the correct information for you about the Vista
Vista will work with only a computer but you need to purchase their dongle to make it work. Cost is based on the number of dmx channels you want.
Just this last weekend Vista came out with a software upgrade and one of the features is that it will now let you use a touch screen.
There are several versions of Vista hardware currently available everything from the large T4 console to just the software and dongle package
The church I attend has a T2 which is a full console. You asked about external wings to make it work. You don't need them to make it work. Now having said that there are 2 hardware options available that allow your computer to be just the brains and you have physical faders etc. They are the S3 control surface and S1 control surface
You will want to check out the Vista App information which is at the bottom of the product page
Also if you have more questions I would suggest you join the discussion forums listed under support as they will be able to answer any of your questions better than I can
Here's the url that you need
www.jandsvista.com
Sorry for such a long post
Bob