Because we planned to implement a new Hyper-V Cluster using Windows Server 2012R2 we had to move to SCVMM 2012 R2 but in order to do this one of the steps we needed to complete was Upgrading System Centre DPM 2012 to 2012 R2.
I have detailed the steps I took below, there may be some differences for your specific configuration but you will get a good idea.
Firstly, there is a list of SCDPM build numbers here;
http://social.technet.microsoft.com/wiki/contents/articles/4058.list-of-build-numbers-for-system-center-data-protection-manager-dpm.aspx