What is your budget and what are you planning to upgrading too? Are you going to move up to a AMD FX-8350, or and Intel i5-3570K? Are you going to wait for the Haswell? What VGA cards were you thinking of upgrading too? What is your time frame in making these upgrades? Also please list your configuration.
You'll get better performance in a dual channel setup with a 8 GB or 16 GB kits then a 4GB + a 8GB. That motherboard supports the new FX CPUs and the price has just dropped in the FX-6300 and the FX-8320 models. The new GTX 700s will be out soon. So I would upgrade the CPU now and wait on the VGA card.