This is a 2033 CAD $ PC. It's not from ncix.com ,but it's going to be the best price for the system you have requested.
https://ca.pcpartpicker.com/list/GjmRgw
Yeah, you should upgrade your monitor to 144Hz as now, you can only see 60FPS on your screen. The PSU is a little underpowered, I would've gone with a 750-1000W PSU for future proofing. Don't worry about temps, those are high ones too.
I own a 960 for 3 years to (changing it this month), I have seen a drop in average FPS but not a very significant drop. Your best bet is doing as @Eximo said
To be fair, your CPU will be bottlenecked in any case of upgrading your GPU, the ram may be upgraded to 8GB as it is usually the best on a budget.
Your best bet is to just buy a new PC.