Today, the latest set of rollups have been released for System Center 2012 SP1 and R2. Delivered as separate rollups, SP1 is now on version 7, while R2 has reached version 3.
Cumulative Updates (CU's) release once every quarter. Each CU is truly cumulative in that it is a large hotfix that pulls together all previously released hotfixes into a single distribution. When customers need to apply the latest fixes, they only need the very latest CU.
Here's where you can get them and which System Center 2012 products are covered in each:
2965090 - Update Rollup 3 for System Center 2012 R2 – Updates provided for: Data Protection Manager, Operations Manager, Operations Manager - UNIX and Linux Monitoring (Management Pack Update), Orchestrator & Service Provider Foundation, Service Manager and Virtual Machine Manager.
2965089 - Update Rollup 7 for System Center 2012 Service Pack 1 - Updates provided for: Data Protection Manager, Operations Manager, Orchestrator and Virtual Machine Manager.