polarix,
I have not known a pre-compiled package of KDE 4.3.3 for Ubuntu 9.10, but there is a debian live cd for KDE 4.3, you can download and try it
from here.
If you want KDE in Ubuntu you may switch to Kubuntu, another Ubuntu flavor, they have KDE 4.3.3 now, you may get it
from here.
Hope this helps. Good luck.