apt-get update
apt-get install cm-super texlive-fonts-recommended context context-nonfree context-doc-nonfree
That command also installs the needed texlive packages for pdftex, metapost, lmodern etc. You should not need to chase down the old teTeX 3.0 packages, which will be removed automatically by the above installation line. To test whether the basics of ConTeXt are working after the upgrade, try: