There's no advantage to the 3225 over the 3220 if using a separate GPU.
Get a better GPU. You should be able to get a 7750 or 7770.
Are you sure all you need is mobo, CPU, and GPU? You don't need RAM, an HDD, a case, a DVD drive, or a PSU?
EDIT: Don't bother getting a 2GB card. 1GB is enough for a 1080p screen in most cases and a better GPU is far more important. It may be worth getting a Pentium G2120.