I would save your money and go with a i5 Core instead. You can grab a prebuilt (if your not really into building PCs) i5, 8GB, 1TB off www.slickdeals.net for $399 (for example http://slickdeals.net/f/7665554-dell-inspiron-desktop-computer-660-intel-i5-8gb-ram-1tb-399-99-staples-com?v=1) then you could go cheap Nvidia 750Ti that is a additional $125
http://pcpartpicker.com/part/evga-video-card-02gp43753kr for a Low to Medium Graphics, but won't play newer titles as much as it is underperforming. If you wanted to get a 'common' GPU to meet all your qualifications, would be a Zotac GeForce GTX 970 4GB for $310 (almost the price of the whole PC)
http://pcpartpicker.com/part/zotac-video-card-zt9010110p you would need to upgrade the PSU to accommodate the power requirements, which is a additional $40 for a 600W+ at least Bronze rated PSU
http://pcpartpicker.com/part/corsair-power-supply-cx600 but you have to check that model for enough connections to power the system PLUS the GPU.
In the end your talking a $700+ machine anyway for PC Game Playing. The Alternative (since you want it NOW) would be to just get a PS4 for $200-400 which DOES play GTA V at 1080P HIGH graphics at 30FPS
http://www.ign.com/wikis/xbox-one/PS4_vs._Xbox_One_Native_Resolutions_and_Framerates PLUS a FREE BluRay Player, FREE Wireless controller , Free Headset for HALF the cost and better performance.