even if it's a budget build, i'd be inclined to spend under a pound more for some brand name ram over 'generic extra value', even if it's still low end stuff.
Corsair 4GB (2x2GB) DDR3 1333MHz Memory Kit Unbuffered.. | Ebuyer.com
there's a pretty big gap in price between the two cpu's you have listed there. obviously the x4 965 would be the better cpu if you can afford it. if you still don't wanna spend that much you could with an athlon ii quad instead.
AMD Athlon II X4 635 2.9GHz 2MB Cache Socket AM3.. | Ebuyer.com
get a psu from a better brand, like this one
OCZ Stealth Xstream II 500W PSU - 3x SATA 1x PCI-E | Ebuyer.com
and yea, if you get that mobo you should have enough slots for the gfx card and the usb card, and it is listed as coming with 3 sata cables and you have 3 sata devices listed so you'd have just enough.