I also have the same model ASUS pre-built that you do and there won't be any significant upgrade from that socket that you have. If you are skilled enough, you can transplant an microATX motherboard in there that would compatible with your parts already, get a new cpu like the i5 you said, and then install the GTX 1060. Right now, I have a 660 TI 3GB model in here and I think it has a lot of length space in the case for a 1060, just measure the inside HEIGHT cause the case is not friendly for a margin of error. a PSU like a CX series should be fine, but be careful for cable management. The case has no room in the back for cable management or for stashing away protruding extra cables, so you might want to go with a smaller PSU with less wires, or a modular PSU. I have the CX 600 V2 and it's just barely fitting, so I suggest going for something within or under it's dimensions. If you dont want to change the motherboard, to prevent bottlenecking , go for the 750 Ti, but if want a 1060, either do a transplant or if that's too tough, you might be better off just saving up and building a new PC entirely. Temps are also an issue if you don't have rear blower components. The pre-built has no fans for airflow so if you want to keep it fanless you should get a rear-blower card and PSU, but for the 1060 w/ an i5 a fan is recommended, and there's a spot near the PSU for one fan. Just remember, the case does have a lot of empty room for upgrades but it's still a microATX case so it's hard to work with dimensions of other motherboards, and you would rather not get the wrong part and end up wasting your money.