If by high-end gaming, you mean playing a game like Watch Dogs or Battlefield 4, then yes your CPU might bottleneck any decent GPU you purchase. I would look into investing in a i5 processor. And as for the GPU, any card within the range of $200-$400 will allow you to play most games on high to highest settings. My personal favorite would be the GTX 770. It will allow you to practically max out any modern game while being future-proof as well. And as mentioned above, it would be important for us to know what resolution you plan to game at. If it is lower than 1080p, than you could probably settle for a card between the range of $180-$230.