Hello,
Could you please let us know if the new Windows 2008 R2 Server would be using the same IP address and Host name?
If yes, then you could go with the Disaster Recovery steps -
Preparing for disaster recovery
http://www.symantec.com/docs/HOWTO54812
Performing disaster recovery
http://www.symantec.com/docs/HOWTO54726
Symantec Endpoint Protection 12.1: Best Practices for Disaster Recovery with the Symantec Endpoint Protection Manager
http://www.symantec.com/docs/TECH160736
If there is a different IP address / Host name then, after performing the above Disaster Recovery and Logging into the New SEPM, any groups and policies that were previously created will be restored as well as the license file. You will also see your clients listed as Offline. As such you will need to connect your existing clients to the new SEPM. Please refer to the document: Restoring communication to clients with a new Sylink.xml file.
Hope that helps!!