Focus on my nikon d3100?

So i got a Nikon D3100 for my birthday which is just an upgraded D5000 and i use the action mode alot because well its fast, and i think its better quality.
But, i'm not sure how to um. Let me think of how to put it, Make a larger focus? I hate taking a group picture and the camera just focusing what's in the middle

You need to get out of the auto modes and use manual instead. Once in manual mode, use a higher f/ number (f/11 should do) to increase the depth of field of your shot.

Set to aperture priority mode, ISO to 100 or 200 and then set aperture to f/8 or higher. That should create a depth of field wide enough even for large groupies.