USAGE FROM MOST TO LEAST IMPORTANT: gaming (elder scrolls online, AC4, watch dogs, most multiplatform games) - Photoshop(CS3)
the games don't have to be maxed out with 60fps, high settings with a minimum fps of 40-45 is okay.
CURRENT GPU AND POWER SUPPLY: NVidia Geforce 9800gt (1GB DDR3) - Bequiet dark power pro P8 750W PSU
OTHER RELEVANT SYSTEM SPECS: CPU: Intel Core i5-750 Quad 2.66GHz
MOBO: Asus P7P55D
RAM: 8GB DDR3
PREFERRED WEBSITE(S) FOR PARTS: /
PARTS PREFERENCES: compatible with current setup
MONITOR RESOLUTION: 1680x1050
ADDITIONAL COMMENTS: as stated above, I want to use this pc for gaming and photoshop. Would it be okay if I only replaced the GPU, or is it necessary to replace other parts as well.
Like I said, it doesn't have to be top-notch, but still decent to play games at a decent framerate and preferably on high settings (at least for the first two years)