Since this is a class assignment, it is against G2G's policy to assist with schoolwork. I suggest you take a look at the vast threads posted in this section to get an idea of what components will work with each other. I can't just list all the components and prices you'll need but I can give you a few pointers on what things to looks for.
Motherboard is essentially the first thing you should pick since video card, processors, RAM, hard drives, DVD-drives all need to be compatible with the motherboard (i.e. what socket, slots, or other things does the motherboard have?)
For example, the motherboard you picked out have DDR2 RAM slot, that means you can only use a DDR2 RAM (memory) so DDR, DDR3, etc. will not work with this motherboard.
For video card, you also need to look at what the motherboard has, there's PCI-Express and AGP slots, so what you need to do is find out what the motherboard has and match it.
Power supply, you need to match this with the case you're getting since there are different sizes for the case (like ATX, BTX, mATX) and there's also the motherboard power connector (ensuring that the motherboard connection and the power supply connector matches, there's 20, 24 and 20+4 pin)
For the processor, there's Intel and AMD, you have to ensure that the processor matches the motherboard again since these two has different sockets so if you buy one that isn't compatible, the processor won't fit and it also might damage both components. After you have picked out the company (Intel or AMD), you need to find out if the processor would actually fit onto the motherboard as if I can recall, Intel has quite a few socket sizes like LGA775.
This should get you started with the list.
Hope it helps.