I have a 2009 Mac Pro 4,1 2.66 GHZ Quad Core system that has the original NVIDIA GeForce GT 120. I do photographic processing with LightRoom and Photoshop and light video work with iMovie. I use a Dell 2407WFP monitor and want to add a second monitor. What would you suggest as the best graphic card upgrade? I can either keep the original card and add a second or replace the original card. Would love to exploit CUDA with Photoshop. The goal is to get to two or more monitors.