Dual Display from ATI 7700

[ray <ray@aarden.us>]

I would like to have my desktop stretched over my two displays.  But my two displays are cloned, the same things shows up on both displays.  How do I fix it?

I have been running Win 8 on the box with a Sapphire 7700.  The displays ran fine.  I just loaded Debian 7.4.  When I 'find' fglrx, none are found.  My source.lost in /etc/apt does not include 'non-free' at the end of any lines, so I put it on the end of 3 of the six lines:
deb http://ftp.us.debian.org/debian/ wheezy main contrib non-free
deb-src http://ftp.us.debian.org/debian/ wheezy main contrib

deb http://security.debian.org/ wheezy/updates main contrib non-free
deb-src http://security.debian.org/ wheezy/updates main contrib

# wheezy-updates, previously known as 'volatile'
deb http://ftp.us.debian.org/debian/ wheezy-updates main contrib non-free
deb-src http://ftp.us.debian.org/debian/ wheezy-updates main contrib

On performing apt-file update, I get:
Package fglrx-glx is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

What can I do to get these monitors working?

I installed 7.4 from a net install.  I don't recall seeing any questions on non-free packages.

I have not built anything on this system so far so I am willing to reinstall if there is a way to get the correct drivers.

I tried installing the ATI Catalyst package as described on:
 http://wiki.cchtml.com/index.php/Debian
but there were errors at many steps.  

I would appreciate any help.

ray