Hi there,
really difficult to offer practical advice without knowing your budget but......
Any PC case that will take an ATX sized motherboard will do. These can start quite cheaply (around £20) and can go up to over £200+
When it comes to a PSU I would recommend a good quality one (I use Corsair myself) and don't go down the path of buying a cheap unit as it will come back and bite you, pretty quickly. Be prepared to pay aound £60 - £100 for a PSU that will give between 550 - 650 Watts which is probably the best range to be looking for with your proposed setup.
Again, depending on budget, there are several options ranging from a standard PSU to one that is fully modular. A fully modular PSU is one that you have separate cables for each item and you only attach those that you need for your particular PC. A semi-modular PSU has the main ATX cables fixed into the unit but peripheral leads for HDD's, GPU(s) etc., that you add as required.