How to reinstall the default graphics drivers in terminal and without internet
The initial graphics driver is the open source xorg drivers included by default. Boot into recovery mode, then select to drop to a root shell. Execute mount -o remount,rw / then make sure you've fully removed fglrx with apt-get purge fglrx -y and rm /etc/X11/xorg.conf then reboot.
If you want to learn how to get access to wifi from a command line instead of a GUI, reference the following website: http://www.ghacks.net/2009/04/14/connect-to-a-wireless-network-via-command-line/