cpu -165usd
hdd -60usd
ram -45usd
9800gt -130usd
4870 -220usd
9800gt total: 400usd
4570 total: 490usd
keep in mind you will need a motherboard, case and powersupply unit with it
although you can reuse your case, but i doubt you can reuse your mobo and psu
@corasked i agree with you although he doesnt ask for a hardcore gaming rig, i think he should have somewhat a decent cpu (note: i dont say amd isnt one)
as for amd recommendation, i wouldnt settle for less then a 6000+
my friend went to get a 6000+ as a site said they sold it for 70eur
so he went to the store and it costed 150eur
so, astro, the decision is up to you to pick one as you have given us a sandbox to play with
look up reviews and benchmarks and post what you would like to have