Hey great gear you got for yourself , that deinately earns the hell yeah and oh yeah!
Ok I wouldn't say you NEED to upgrade your ram as it does the job fine, but if you would like some more performance then you could go with DDR3 1600 or higher with lower timings, only then you will see some increase, bit it won't be massive.
DDR3 is more affordable these days and I don't believe you need 16GBs of it either, but if you just want to upgrade it cos you want a little more performance and oh yeah then go for it.
You could always look at the Corsair Vengeance or GSkill ram, those two are very popular amongst most users.
Look at either 1600 or 1866 with lower timings.