First of, since you're using a laptop it's possible that your video card doesn't properly support resolutions higher than the native res of the laptop's screen.
That said, try hitting the 'Fn' key + the monitor icon key (usually one of the Function keys at the top of the keyboard). This tells...
No, you don't incur any roaming fees unless you're actually using your phone on another carrier's network. Watch out for data roaming charges though... if you have visual voicemail you could be hit with data roaming fees whenever someone leaves you a voicemail whether you check it or not. This...