It is a Subversion repository at
https://gccg.servebeer.com/ccg/trunk
Ask for username and password. You can browse directly with your web browser and download individual files. If you want to intentionally mess around and break your client
Well, seriously, at least graphics are safe to load alone. Other files you should know what you are doing, if you mess around with files and putting them into the different installation - may work or may not.
The best solution is to get subversion client, which updates every single file that has changed since the last update. That should be the exactly the same development version i am using myself. Yes, that is probably broken more often than official gccg-packages as well. Your choice.
More about subversion:
http://subversion.tigris.org/
You can ask help online. I know mainly linux commandline, though, but i assume there will be soon people more proficient with subversion.
One more thing. At the moment windows binary is in different directory as it is in usual gccg-packaged version. You may need to copy content of the module_windows32 to the root directory of the stuff and then Metw.bat works as usual. We are working on it (as soon as i get 'wlk' working on it

