[Trisquel-users] Monitor resolution (complete beginner)

[genghis]

Hi,
   I've just installed Trisquel, and the highest screen resolution available  
is 1024x768. My monitor's native resolution is 1680x1050, so I'm assuming  
it's not recognising my graphics card (an NVidia GeForce GTS 250). I'm pretty  
much a complete newcomer to GNU/Linux and have no experience with the command  
line (learning things like that are part of the reason I've installed  
GNU/Linux, but that doesn't help right now).  Can anyone walk me through  
whatever I need to do to gain access to higher resolutions?