Hi,for KDE you can use packages from Alioth (http://pkg-kde.alioth.debian.org/kde-3.4.0/). Please note that this is NOT a third party site, since these packagers are the same of the one who package the standard Debian KDE..... You must add these site in your /etc/apt/sources.list and then apt-get update & apt-get upgrade. That's it.....
Regards, MC