I was assuming you were intending on an AMD kit because you had selected an AMD-compatible motherboard and listed it in post #2. That being said, for a computer of this budget, I should think an AMD system would suit your needs fine.
For an mATX case, here
is a Cooler Master choice. Then you would need to change the motherboard to mATX also, so it will fit. Here
is a nice Gigabyte example, although a little more expensive. It also has onboard video, if ever you have a problem with video cards.
And finally, if you are going to be using such a small case, I would recommend you upgrade to a modular power supply, otherwise you'll have cables everywhere inside that case. This
one is a little expensive again, but well and truly worth the money in my opinion. It's an excellent unit.