Here's my problem

I have two screens. One is a 22"led monitor and the other is 42 inch led tv. In windows 7 I run xbmc on the second monitor. I'm trying to mimic the same function in setting xbmc to display on the tv only.

So I installed the latest x64 linux drivers from ATI. I configured (using the catalyst control panel) using single display (multi desktop)

I then got a white screen with black x so I enable xinerama. with xinerama enable I got the displays to work correctly, however I received an error when I tried to enter display settings to change the launcher location. the error message was " "randr extension not present ="

So I tried to install libxandr2 using terimal but here's what I get

trev@Lrig:~$ sudo get-apt install libxander2
[sudo] password for trev: 
sudo: get-apt: command not found

I'm at a loss now because I can't find a solution for the xandr error message.

I'f my specs are important amd athx2 6400+ ghz 8 gigs ram radeon hd6950