Don't get an A4, or any APU for that matter, unless you decide not to get a dedicated graphics card. You're better off spending a little more for a G2020 or similar from Intel or if you go AMD something like the Phenom II X4. It might be a tad more, but it's miles faster, and the motherboard will be cheaper as well to compensate (well perhaps not that much if you go H77, but the A4 is going to have such horrendous performance.
Get 2x2gb of RAM rather than 1x4gb, unless you're planning on getting another stick of 4gb in the near future. Having 2 sticks of RAM allows you to use dual-channel mode, which doubles the memory bandwidth.
$70 is a lot for a case on that sort of budget. I'm sure there are some quality $30-$40 offerings that would suit you much better. Check out the Fractal Design Core 1000.
Don't buy a CoolerMaster (CrapperMaster) power supply. They are notoriously bad unless you get a really high end one. Get a CX 500, again a tad more, but you pay for quality (i.e. not to have your computer melt), and should be saving enough when you swap out the case anyway.
M