Adjust my page to 100% coverage

[neogest.com.br]

Can anyone help me set my page to 100% coverage?

I am having difficulty in setting this bit, when you put 100%, leaving the columns were heading.

I have some way of fixing these positions?

Left column on the left side
Right column on the right side
Center column, centered

Please, I am researching this for days and could not adjust.

/* global layout */
#page {
   width: 980px;
   margin: 0 auto 2px auto;
   text-align: left
}
div#logo {
   float: left;
   width: 27%;
   margin-top: 1em
}
#header_right {
   float: left;
   margin-bottom: 15px;
   width: 73%;
   text-align: right
}
#left_column, #center_column, #right_column { float: left }
#left_column {
   clear: left;
   width: 191px;
   margin-right: 21px;
   overflow: hidden
}
#center_column {
   width: 556px;
   margin: 0 0 30px 0;
   overflow: hidden
}
#right_column {
   clear: right;
   width: 191px;
   margin-left: 21px;
   overflow: hidden
}

[neogest.com.br]

Please enable someone to help me?

[scholl]

page edit to width: 100%;
header edit to width: 100%;
body edit to width: 100%;
footer edit to width: 100%;

edit left_column (width), center_column(width), right_column(width)