I want to play some of the latest pc games on my laptop what do i need?

I have only been using my computer for stuff like browsing and music and movies etc and i want to start using it for gaming. I have an acer extensa 4420 with 3GB of ram, i have an AMD Athlon 64 x2 dual core processor tk-57 1.90 GHz,.I am running on 32 bit operating system but i can switch to 64 bit, i am running windows vista service pack 2 and i have a ATI Radeon x1200 series video card.chip type ATI Radeon x1200 series(0x791F). dac type internal dac(400 MHz). adapter string ATI Radeon x1200 series. total available graphics memory 1406mb. dedicated video memory 256mb. system video memory 0mb. shared system memory 1150mb. is there any other info needed because i want to find out if my laptop can be used or if i need a new one because everything works fine but i cant play a lot of the newer games any help would be appreciated since if it can be helped i would rather just buy a new video card thank you for your time