How to change Body width

Hi, I'm setting a website with only one column, no sidebars. The actual width of the body is too high (1140 px I think), is there a way (CSS?) to reduce the body width to a total of 940px and width of text 640, so there will be a distance from text to the border of body of 150px? Hope it's clear :) This is the site http://www.sr22bond.info/ Thanks for your help!