GNOME ng IN 13.1

I really wanted 12.3, but got 13.1 instead. Gnome 3.x does not work well on my machine (Dell Dimension 2400 Celeron 2.4ghz, on board graphics). Graphics are inconsistently displayed and response-time to mouse/keyboard is abysmal. Would like to try KDE, but as I probably don't need all of its packages, how do I install KDE functionally equivalent to Gnome? How do I change the startup to use KDE?

PS: I only have a CD drive on this machine. Used A CD iso for network install for 13.1. If I could find one for 12.3, I'd just overwrite 13.1 with 12.3 and pick KDE instead of Gnome.

-GeorgeOrwell