I have an Alienware 18 R1 with a duel NVIDIA GTX 860m graphics card. Am I able to upgrade the graphics card to a NVIDIA GTX 1060m card?
Yes you sure can. You can even go to the 1070. I have upgraded my M18x R2 to the 1070 and it is a very similar process for the 18. Check out this thread.
Alienware M18x R2 (i7-3920XM, GTX 1070, 16GB 1866MHz)Alienware M18x R2/Alienware M17x R4/Alienware M17x R3/Alienware M15x/Alienware X51