Here are 100 examples of your system.
http://www.userbenchmark.com/System/Dell-Inspiron-530s/2648
The best CPU is Q9650. Q9550 is cheaper.Also note the lack of Radeons R9-3xx and up. They won't work (including R9-285).
Your computer won't have a 6 pin PCIe cable so avoid GPUs that need one. GTX750Ti is popular with this CPU. I don't know how it would work with the faster 1050 series.
Don't be afraid to put a PSU, or video card in there. It can move forward when the time comes.