Upgrading... Help!

[Phyc0]

Hey,

I'm thinking about upgrading my PC so I'm prepared for Windows 7 and so I can play high-resolution games which I can't play at the moment...

Here's my current system spec (Don't laugh at it ):

CPU
Intel® Pentium® D CPU 2.80GHz

CPU Speed
2.80 GHz

Operating System
Microsoft Windows Vista Home Premium Edition, 32-bit (Build Service Pack 16001)

Video card
NVIDIA GeForce 7500 LE (GeForce 7500 LE), 256 RAM, DirectX Version 10.0

Sound Card
Speakers (Realtek High Definition)

DVD drive
LITE-ON DVDRW SHM-165H6S ATA Device (This doesn't work at all.. )

So I guess it's probably a better idea to buy a whole new PC... or?

Greetz,
Phyc0