Are you able to open the synaptic package manager? Go to: system > administration > synaptic_package_manager. Then click: edit > prefereneces, and make sure the universe and multiverse repositories are enabled. They should be enabled by default. Then close that box and click the "reload" button on synaptic. You can then search for and install any software through synaptic.:
As far as I know you should be able to get just about any software that is available in the software center through synaptic.