need help in desiding on what to get

my mobo is GA-MA790GPT-UD3H
cpu-amd am3 single core 2.7
ram- ddr3 4gb
hdd- sata 750gb
psu- 750
graphics unknown but played tron fallout 3 new veges but just cause 2 or star wars force unleashed didn't work on it

so i was thinking about getting 1 of these 3 items
Patriot Memory 'Sector 5' G Series 4GB (2 x 2GB)
AMD Athlon II X2 265 Regor 3.3GHz 2 x 1 MB L2 Cache Socket AM3 65W Dual-Core
XFX ATI Radeon HD 5670 1 GB DDR5 DVI/HDMI/DisplayPort PCI-Express Video Card HD567XZNF3

im leading towards the cpu or graphic card ,my pc aint slow. also can you tell me why you choose that item as i believe it will help me choose

thanks