Open GL 3.2 was release on August 3, 2009. I think just about anything somewhat recent will support it.
Honestly, the version of Open GL isn't something you should worry about unless you have a very specific use case. Most importantly is, how much are you willing to spend on a newer graphics card? That will help narrow things down. Then I would look at your motherboards specifications - like the version of PCI Express is supports. Depending on how old your other components are, you may end up needing an upgrade for your motherboard, processor and/or memory.