I had a score of 2150 Last week. Now, I have added an extra 512Mb of ram (total 1Gb) and OCd my CPU to an Athalon 3200+.

My benchmark score is now 2250. An increase of only 100. Does this sound right?

Yes, Ram and CPU won't have much affect on 3DMark05 scores. OCing your video card might get you another 100-200 points but any big gains will require a new X series ATI card or 6x00 nVidia card.

i got 5476 on 3Dmark05. heres my system specs :D

Intel P4 3.2Ghz 1MB @ 3.9GHZ
OCZ Eliminator2 Heatsink/Fan (For up to 3.2Ghz =P)
Artic Silver 5 Thermal Paste
2GB (1GBx2)*DDR400 GEIL Dual Channel @ 245Mhz
PNY 6800GT 256MB @ 425Mhz GPU 1140Mhz RAM
Hitachi*SATA150 80GB
ABIT IS7-E

3Dmark05 Score: 5387