I currently am running AE v.184.108.40.206 and would like to update to v.12.0 to take advantage of the Cinema 4d integration. How do I do this? I see a free trial download available but is there a way to just update my current version?
You can purchase the new version at special upgrade pricing if you have an older version (as you do). Simply select the membership plan for existing CS customers in the drop-down on this page.
So this isnt just an update for CS6?
The latest version of CS6 is 11.0.4
After Effects CC is version 12 (the latest update is 12.2.1).
So, no. It's not an update to CS6; it is a completely new version (with a TON of new features besides the C4D integration). You can read about the new features in 12.0 here, what's new in 12.1 here, and what's new in 12.2 here.
You can have a decent level of integration with C4D with your current version. You just need to download the plugins from Maxon and you can import C4D scenes into AE after you've rendered them.