Pete, allow me to put my arm around you and look back on your build first. Besides some FPS and shooters, you never got the video card you really wanted. But you now want more power in those and also create content "a bit". That's some cryptic bullshit dude. This is hindsight build vision 20/20. Do you need 4+4 cores for games? Do you need that for content? Yup, i7 was overkill and $100 over an i5 Sandy would have done very well.
I digress and sorry I couldn't help you build and budget this prior: I really feel you want an AMD video card and what you can afford if you have $300 or more. "A Good Match" would be another $700 card you don't use like you'll never use an i7 CPU...and don't take an insult out of that at all. I'm just toying with the verbiage of "Matching". You over spent on some stuff bro and left something critical to your usage out. I won't ponder why here but it's in my mind.
Find what you can spend (and perhaps tell us after that spending spree), and it's more than likely an AMD video card that you want to use. Mention your screen(s) and all that and it will be more than a peter measuring contest that we're helping you with here. The base build hurt so much that you had to wait on a video card. If you have $600 now, I guess a 7990 will be what you buy as that's the best card out there in that price range.
What's exactly not working with your gaming or the pro level software that costs a lot of money too that is letting you down currently? Could you survive with a Craigslist GTX560Ti for $80 a pop? If you want reassurance of the highest video card you can get, you won't get it from anyone sane or with any technical background into this topic. I see flaws in your build so just buy what you want. Whatever money you have, spend it all.