width problem with neptune theme.

Hi,

I need some help to make the width of page-heading 100% so it stretches from side to side.

Theme: Neptune
https://s9.postimage.org/bmb5pvbb3/bigproblem.jpg se my link
css:
#page-heading{
position: relative;
margin-bottom: 40px;
padding-bottom: 40px;
background: url( images/border.png ) top repeat-x transparent;

}
#page-heading h1,
#page-heading h2{
font-size: 21px;
color: #e0e2e5;
margin: 0px !important;
}