For modifying the HUD, I"d look here: http://developer.valvesoftware.com/wiki/Category:Programming (User interface (VGUI)).
What do you mean by output on the enemies? Are you looking for a way to count the kills?
Yeah, I think you can get around that though, if you parse the map's entity data yourself.
I don't think that tutorial is the best way of doing it though (I don't think it will display text when characters speak). Are you doing this with a mod or plugin?
There are some suggest console commands here. Getting a new graphics card would be the best solution though, because some Intel graphics cards aren't compatible with Source.