Don't touch that Gigabyte PSU. It's a POS. Instead, pick up something cheap, but good quality, like Antec's Earthwatts 380W unit.
When comparing GPUs, I prefer to use Tom's monthly hierarchy. According to that, if it's the HD 4650 DDR2 version, the GT 430 is better. If it's the DDR3 version, the 4650 is better. Though, I will say if you can spare an extra $10 or so, the HD 5670 is even better than both.
I'm not sure how much you're paying for that RAM, but some faster 1600 mhz sticks are only $40 on Newegg. Right now, that's the same price as 1333 mhz sticks.
I'm also not sure which exact board you're looking at (is it this MSI 760GM-PP3?), but I'm willing to bet you can do better. That's an older chipset, which means you won't be able to get USB/SATA III support. It also only has two RAM slots, which greatly limits the upgradibility of the board. I'd look at this Asus M4A77TD that's around the same price. It also doesn't have USB 3/SATA III support, but it does have 4 RAM slots. It's also from a brand that's better known for quality.
I should add that if you're buying from a local brick-and-mortar store, you're likley paying a lot more than you should and drastically limiting your options. Can you buy from Newegg?