How to change screen resolution to 320 x 240?

[ai4281]

Hey everyone. I was trying to run Sims 2 on the diamond, but the game only takes up quarter of the screen. It's running at 320 x 240, but leaves rest of the screen black while taking up the left-upper corner only...

I'm wondering if there's a way to run the game at Touch Diamond's resolution, or to change Diamond's resolution to 320 x 240.. Anyone have a solution to this?

Thanks.