|I'm not sure why the BIOS would have anything to do with that, but it is good you got it working.|
There are settings to display things like icons and text at larger sizes.
When using ANY LCD display it is always best to run it at the native resolution. No other resolution will look as sharp.
The resolution you need may or may not be available. Try updating the video drivers for your chip set. The newest drivers will be the most likely to have that resolution as an option.
Many computer displays use 16:10 ratio. The display you are using may be designed to be used for movie/TV viewing because it is 16:9 ratio.