Graphics cards make a difference, but unless you have the other components to support it that card isn't going to make any difference. No one device is the key.
Take the person who decided to up grade their graphics card so that they could play BF2, they purchased it and installed it only to discover that their PSU wasn't large enough to support it. After purchasing and installing a hefty PSU they then found out that the 512MB of RAM was being sucked up like it wasn't even there, another purchase of another 512MB of RAM finally got their game going.
A smart combination of Graphics card and RAM should set things alright for a gamer. Also it depends on the game you are about to play. Games like `Stalker: Shadows of Chernobyl' though recent require a minimal configuration. On the other hand, `Elder Scrolls' requires you to have a solid configuration for a uninterrupted game play.
Considering that you have 1GiB of RAM, you need to get a decent graphic card if you already haven't got one.
defrag your disk and go from 1 gig to 2 gig ram. Before i did that i used to take ages at that "Verifying Client Data Thing" and it used to hang when opening/closing battlefield and joining/keaving a game. Now the problem is solved.