If you want more pressure just turn the nut on the long thread in the pressure switch to the right (each complete turn should increase the pressure about 1-1/2 lbs. Of course you should reset the pressure in the tank to 2 lbs. below the cut-on pressure.
Then your wife won't like the constant change in pressure while taking a shower. Install a Cycle Stop Valve http://www.cyclestopvalves.com/index2.html. She'll love the constant pressure.