How would I improve my computer build?

[Sykez]

What's a good and cheap effective way to improve my computer? It's quite crap. I haven't got a great budget to spend so far.

System
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Manufacturer Gigabyte Technology Co., Ltd.
Model 945GCM-S2L
Total amount of system memory 2.00 GB RAM
System type 32-bit operating system
Number of processor cores 2
64-bit capable Yes

Storage
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Total size of hard disk(s) 466 GB
Disk partition (C 226 GB Free (270 GB Total)
Disk partition (D 54 GB Free (195 GB Total)
Media drive (E CD/DVD
Media drive (F CD/DVD

Graphics
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Display adapter type ATI Radeon HD 3450 (Microsoft Corporation WDDM 1.1)
Total available graphics memory 1023 MB
Dedicated graphics memory 256 MB
Dedicated system memory 0 MB
Shared system memory 767 MB
Display adapter driver version 8.56.1.15
Primary monitor resolution 1280x1024
DirectX version DirectX 10