800x600 really won't look a huge amount different on a smallish 15 inch screen. It will look that much better for being a vaio screen anyway to make up for it. It's really down to fiddling with your settings on any game. Start playing the game on as high detail as you'd like to have it, and if it isn't running that well, turn some of the details down or lower the resolution. I personally would change the res and keep the details but it's personal preference.
Unfortunately the graphics card is where Sony really let you down, 64mb doesn't cut it nowadays for games, so in a year or two it's really going to show your computer up. And you can't replace it. It's a big shame as the hardware in general is first rate, and for laptops as pricey as these that EMPHASISE the quality of the graphics to give you a crap grahics card is maddening. I'm in the same boat as you man, mine's 64mb. And to really stick the knife in, Sony don't update the drivers either. Or at least it's been 8 months since the last one.
*Sorry didn't mean that to become a rant lol*
