BF2 is the most demanding and graphically intesne game on the market, for this reason the specs are obvously MUCH higher than normal games, but then as a player one is rewarded with lush graphics and photo-realisitc scenes.
Basically steven, IGNORE minimum specs on pc games, these are just there so the makers can sell more copies. A game may play with a minimum spec machine but it wont look right or play smooth etc.
To run BF2 smoothly on high you need at a bare min:
2.8ghz processor
1024mb of 400mhz ram (2gb is recommended)
2gb Hdd space (must be NTFC partitioned)
a 128mb video card, however, this is a grey area as not all 128mb cards will play the game. Basically any geforce card above a 6600GT or any nvida card above the 9700 will work. I will write a small thread about video cards are i cant explain it all in here.
Steven i would surgest that, before you upgrade you post your currant system specs (including who made each part,eg:cruial ram or nvida graphics card) on here and then we can advise you on the best parts.
99.9% of the time the cheapest place to find your parts will be
www.ebuyer.co.uk. I used them for my trade accounts when building, very reliable and about 40-50% cheaper than PC world.
Ive almost finnished the first article, i will try and get it online by 10 but im a bit backed up this evening!