Since it is a standard size ATX motherboard, you can go to a site like newegg.com and do Computer Cases>ATX Cases>Mid Tower Cases and any of those will fit everything you have nicely and then some.
Also, don't get a case WITH a power supply in it. The PSU they put in the cases are normally stock and low quality. Invest a few dollars and buy a Power supply seperate. Here is a great deal:
Although you can find them cheaper as well. Be smart when buying a power supply and look for brand names like Antec, Sparkle, Fortron, Enermax... they are all well known and dependable brands.