TI Connect software?

[Me]

Where can I buy TI Connect software?

I just got a TI-83 plus graphing calculator for school because one of my friends who is a year older than me told me we needed one for geomentry.
Please do not lecture me on you shouldn't be playing games in school. I probably won't even be playing them in class I just want them like if I go somewhere right after school or something.
I've been looking on this site
http://www.ehow.com/how_2203274_graphing-calculator-games.html
in step 6 it says open MirageOS. What is that I think I saw it on ticalc.org is that what they mean because I've seen the connect software on amazon and it comes with a disc. Do I need that?

I want to find the software on an actual store website not something like amazon or ebay. Something like Circut city, target best buy ect.
http://www.ticalculators.com/images/usbcable.gif
this is a pic of it but I need to find it at a store