AFAIK PS2 & XBox games are supposed to be 4:3 unless specified to be 16:9. (Valkyrie Profile 2 (ps2) had a 1080i mode for example.) If the game is actually supposed to be 16:9 (having an option ingame), then simply have your TV stretch the image to your liking (as you have a 16:9 TV I assume it has an option for this).

Your capture card most likely assumes a PAL in & output, thus giving you 4:3.