Can i add 2x8GB ram to a dual channel motherboard with 2x4Gb?

I am using a computer with a dual channel G.Skill Ares F3-1600C9D-8GAO 8GB (2x4GB) DDR3 ram which i have no trouble with when playing games however it is slow when rendering projects in Maya. If i were to buy buy more ram, would it be possible to add 2x8Gb chips or better to just add another 2x4gb ones?
I would like to have as much ram as possible but i cant afford much due to paying for university, textbooks, etc.
What would be the best course of action here as i do not have the time to render my projects to the quality i would like with the amount of ram i have?