Copying the database is simple enough, but you just can't copy the entire SQL installation. That is heavily integrated with the OS, so you will need to use the installer for that. (Make sure you're collation is set right!)
We run a VMware virtual environment, so when I moved from 9.1 to 10.2 I just set up entirely new VMs for the application and database servers. As a rule I much prefer clean OS installs to in-place upgrades. By the way, 2012R2 isn't supported for 10.2 M020, so I'm only running that on the development system. Production is running 2012. 2012R2 is supported for 10.2 M030.