I value your opinion but there must be a way to squeeze more life out of this thing.
Some computers don't have a realistic/cost-effective upgrade path. This is one of them. Get over it.
Its in excellent shape and runs almost everything i want it to.
So why do you want to monkey with it? Leave it alone. It's fine (by your own admission).
i cant afford a new machine for a while
This is the heart of the problem. You are suffering from boy's toy inferiority complex. Your girlfriend sounds like a sensible lady.
and i want to atleast make this one better while im stuck with it!
Buy this 2003 vintage Pentium 4 some more RAM maybe? if it isn't maxed out... You can fit 4 x 512 MB in there... but the mistake was made at purchase time. You can't make a silk purse out of a sow's ear.
Unfortunately, cost-cutting measures such as integrated graphics and a slow memory hamper performance. Righting the configured wrongs, as well as adding a display (Sony sells that separately), will add to the VAIO PCV-RS320's $1,099 price, making comparable alternatives from Dell, Gateway, and HP more attractive.