I see you are using a laptop so i think your graphics card's memory are too low for resolution greater than 800x600. GTA4 calculates your resources for all the graphics settings you choose for the game. It wont let you choose graphics settings that exceeds your memory.

you can by pass this restriction which you can find it on the main GTA4 thread.

http://forum.lowyat.net/index.php?showtopic=935271&hl=GTA