@Curtis6767, if you are getting an error the the repository isn't available, then you do have it in your /etc/apt/sources.list. You can either disable the extras repository using software sources either in the software centre, or synaptic, or change it to Precise, in order to stop the error. See the screenshot. You can also disable it from the command line using your favourite text editor:
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
#deb http://extras.ubuntu.com/ubuntu precise main
deb http://ca.archive.ubuntu.com/ubuntu/ quantal-proposed restricted main multi$
# deb-src http://extras.ubuntu.com/ubuntu quantal main