I am no expert, but Crucial shows that your Dell can use PC2700 (DDR333) or PC3200 (DDR400) memory. Personally, I would probably go with kingston's, corsair's or OCZ's "value" version stick. Little more than the $60, though you might be comfortable with a cheaper brand.
More ram is always better.
I don't think I am qualified to help you with the video card. Skuzzy would be best to ask.