Need help with specs

These are the system requirments for a program I want to use:

Minimum System Requirements:
• Windows XP, Windows 2000, Windows XP 64-bit
• 512MB System RAM
• 2 Ghz Intel Pentium 4 or equivalent processor
• 128MB Direct3D compatible video card
• and DirectX 9.0 compatible driver;
• 8x DVD-ROM drive
• 4.6 GB free hard disk space
• DirectX 9.0c (included)
• DirectX 8.1 compatible sound card

Supported Video Card Chipsets:
• ATI X1900 series
• ATI X1800 series
• ATI X1600 series
• ATI X1300 series
• ATI X850 series
• ATI x800 series
• ATI x700 series
• ATI x600 series
• ATI Radeon 9800 series
• ATI Radeon 9700 series
• ATI Radeon 9600 series
• ATI Radeon 9500 series
• NVIDIA GeForce 7800 series
• NVIDIA GeForce 6800 series
• NVIDIA GeForce 6600 series
• NVIDIA GeForce 6200 series
• NVIDIA GeForce FX series

What I have is this:

Dell Dimension 3000

Intel Pentium 4 2.8 Ghz

512 MB RAM

82865G Graphics Controller 96 MB RAM

I'm a complete computer noob, so I may not have given you all the neccesary information, but what upgrades do I need to get (if any) to run the program?

(And where do I see how much free space is on my computer? 4.6 GB sounds like a lot).

Thanks so much!