apt-get revert

I'm running Debian testing on my box at work.

apt-get update
apt-get dist-upgrade
apt-get install pixieplus
restart machine, to verify computer can be started in the event of a
power failure.

kde has now been removed and is uninstallable.
(pixieplus is a kde package.)

apt-get install kde
**lots of error messages, saying things like I need to install kdelibs3
and koffice but it's not going to be installed.

kde was running ten minutes ago. Thanks to apt-get pulling testing
sources, kde is now not running. How do I let apt-get revert to the
older version of kde? This much-needed feature seems to be an extremely
popular one to keep completely buried in Debian, no man pages, no howtos
explain this. I keep hearing, keep your debs, it has the information
you need to restore a botched install. Great, how do I unbotch?

an acceptable answer would be, how do I install gnome? at least I'll
have some kind of gui at my desk until Debian testing gets its act
together in two weeks. apt-cache search gnome seems to pull up all the
gnome applications, but there's not "just gnome" like there is with kde,
and installing any gnome-only package doesn't resolve the dependency to
include "just gnome". I tried gdm, but it's not 'enough', as I can't
get past the login prompt.

--Alexander