You need to enable the XMP (Extreme Memory Profile) in your BIOS for 1600 mhz memory. Nothing else will be required.
By the way, its actually running at 1333 right now (667 x 2 for DDR, or double data rate)
When it says 800, it will be running at 1600.
Be advised though, that if this is a prebuild like an HP, you may not have the option to enable an XMP profile, and 1333mhz is all you are going to get.