Starcraft 2 Graphics help

[Unholyfox]

Hey, I've looked up a few guides on how to make my computer run faster, and some of them have helped by adding a few FPS.
At Average im running around 20-25 FPS, all on LOW!! I looked it up and the average is 60! Can anyone help me to improve my graphics as well as FPS. Im only in highschool and donot know much about this hehe. But here are my system settings :

Operating system:Windows 2.5.1.2600 (SP 2)

   
• CPU type: Intel(R) Pentium(R) 4 CPU 2.40GHz
• CPU Speed (GHz):2.411
• System memory (GB):1.249
• Graphics card model:VisionTek Radeon X1300 Series
• Graphics card driver:ati2dvag.dll
• Desktop resolution:1440x900
• Hard disk size (GB):170.094
• Hard disk free space (GB):170.021

[coolflip]

Have you done a defrag in the last few weeks? It really helps your system, and may raise your fps by around 5-10, along with everything your computer does.

[Unholyfox]

acually i had 2 days ago, it helped somewhat but not too much, i tried again today and it said "Defragmentation not needed".
also on a sidenote I had 3 Drives:
C: total size is 74.5 GB
D: 125 GB
and G, which my dad just recently put on my computer, he had found it laying around hehe
G:170GB

On C and D It is used about 50%.. Now i was wondering if there was a way to put the memory from G(170GB) on to C to make it around 250GB Drive or so..?