Computer

[plutomaniac]

The PSU should be ok for normal use meaning no overclocking. Currently you could upgrade to a Intel Core 2 Quad cpu (meaning 4 cores vs 1 you have now). 4GB is the maximum this mobo supports so you're fine there. The HDD is fine. For gpu the 7770 mentioned below. So if you just upgrade you need approximately:

170$

However, you would be upgrading a dead platform and soon new changes will be needed. So I suggest a platform change. For your current budget I suggest:

Graphics Card: AMD Radeon HD 7770 1GB (best value for money) - 100$

RAM: 4GB DDR3 1600MHz (budget constrains, otherwise 8GB) - 48$

Motherboard: ASUS M5A78L-M LX PLUS (budget constrains but descent board) - 55$

CPU: AMD FX-6300 (budget constrains, otherwise AMD FX-8350) - 120$

Total: 323$

Optimally, for a normal "budget" I would suggest these changes:

RAM: 8GB DDR3 1600MHz - 75$

CPU: AMD FX-3850 (best value for money, great multitasking & gaming) - 200$

Total: 430$

To buy & build a complete new system 500$ are needed(this includes gpu, psu, ram, mobo, cpu, hdd).