You manual will tell you where to go to change memory settings. It can be tricky to find if you don't know what your doing. It should be set on "auto", you'll want to change that to manual.
You need to look at the sticker on your ram and then go in bios and manually set the speed (1600), timings (9-9-9-24 or something similiar) and voltage, (hopefully you bought 1.5v ram) according to what it says on that sticker.
So you'll set the ram from 1333 to 1600. Then you'll check that the voltage is correct (should be 1.5v, if not you bought the wrong ram). Then set the main timings. So if the sticker says 9-9-9-24, that's what you'll change it too.