Your CPU is from the "Sandy Bridge" 2xxx generation, and you can put in an "Ivy Bridge" 3xxx CPU.
The Ivy Bridge architecture was just Sandy Bridge in a smaller manufacturing process, with minor optimizations. The main selling point was about a 20% reduction in power consumption, while having slightly better performance.
The best upgrade would be a Core i7-3770K (4 cores / 8 threads), which is fully supported with the latest BIOS. The minimum upgrade i would consider would be an i5-3570K (4 cores / 4 threads). Everything below doesn't give enough advantages to your current CPU.