You used to be able to download Camera RAW separately from their site (as a registered user)...at least for a few years after CS2. That's how I kept up-to-date. Have you checked their support/download area - just in case?
http://www.adobe.ca/downloads/updates/
Right at the top - maybe try that (if you haven't already). At least in the CS3 era, downloading the file here allowed me to replace/update my cs2 raw stuff.