"Physical Memory Size 479Mb"
As memory still tends to be in multiples of 256, this indicates you're probably running onboard graphics rather than a dedicated VGA card, this would seem to be confirmed by the comment
"System Slot AGP Status Available ".
So the two obvious suggestions are :-
1) Go to Crucial UK for a RAM upgrade click here .
2) Install a dedicated AGP graphics card, advice as to what to go for will no doubt come from the cognoscenti when you tell them what you want it to do and precisely how tight your budget is.