You can't upgrade the video card in that laptop. 6GB is not dual channel unless you have 4 RAM slots with 2x1 and 2x2 sticks in it. Going over the speed your chipset supports for the RAM would be a waste of money, you can likely use cheaper slower RAM.
Generally, GPU upgrades aren't very doable. It's complicated to do and even if you can do it, there's the question is the power supply good enough for the new GPU and if it's not, there's nothing you can do about it. Also there's the problem of finding the GPU, I don't know about any places that sell laptop GPUs.