Here is a quick howto on upgrading the GPO templates on a Server 2008 R2 domain controller with the newest ones from a Windows 8 machine. There are a few additional ones that you can get from a Server 2012 machine as well that are not included with Windows 8.
You can now download the new GPO Templates from here.
**OLD WAY** Use process above.
So here goes.
Open an elevated cmd prompt and run the following commands.
cd /d %windir%\winsxs mkdir c:\temp mkdir c:\temp\admx\PolicyDefinitions mkdir c:\temp\admx\PolicyDefinitions\en-US FOR /F %i IN (c:\temp\admx\admx.txt) DO copy %i c:\temp\admx\PolicyDefinitions\ FOR /F %i IN (c:\temp\admx\adml_en-us.txt) DO copy %i c:\temp\admx\PolicyDefinitions\en-US\
This will copy all of the new templates from your Windows 8 machine to the temp location. Now logon to your Domain Controller and browse to c:\windows\ and rename PolicyDefinitions to PolicyDefinition.orig. Now you need to copy the PolicyDefinitions folder you just created in c:\temp\admx to your domain controller in c:\windows\. Open up group policy editor and enjoy your new upgraded templates.