The 'apt-get install' command requires you to tell it what package(s) to install. Did you mean to say 'apt-get upgrade'? Also, personally I prefer just to update the apps I use alot and install the missing ones I need. I don't ever use the 'apt-get upgrade' command.

As far as firewall apps, there's guarddog and firestarter. Guarddog uses the iptables I believe, but is GUI-based. Firestarter seems to be the easiest to use from what I can tell, but doesn't seem to have near as many features.