Far Cry 3 is much more graphically demanding than any of those games, even on low settings. Part of the problem is Far Cry 3 tends to stutter a lot if your framerate drops below 50FPS, so for a smooth experience you need a faster graphics card, as 30 FPS in Far Cry 3 is much choppier than say 30 FPS in Call of Duty.
I would like to know more about your system and how much you would be willing to spend before I could really make a recommendation on a graphics card. You may also have to get a better power supply in order to run a significantly better graphics card. Also if you have a slower CPU, there might not be much benefit in spending a huge amount of money on a graphics card as slower CPUs can hold back the faster graphics cards out there.