How to widen a container

Hello,
I found a really nice WP Template that fits my subject like a glove. My site is http://petchristmasstocking.com/ and the template is V4NYChristmas3 1.0 by Vanessa Ferreira
The problem is that the left, main, column is only 330 pixels wide and I would like to have 500 pixels in width.
I can go into the CSS and change the size of the containers and that works but the background from the sidebar does not move with the sidebar and so stays in the middle of the template.
I tried to contact the author of the template but everything is shut down.
Can anyone here help me please?

I am placing the CSS code below my signature
Thank you
Michael
/*
Theme Name: V4NYChristmas3
Theme URI: http://v4ny.net
Description: Christmas theme number 3
Version: 1.0
Author: Vanessa Ferreira
Author URI: http://v4ny.net
*/
body{
background-color: #FFFFFF;
background-image: url(images/bg.jpg);
background-repeat: repeat-y;
background-position: left;
text-align: center;
margin: 0px;
}
#container{
background-image: url(images/bg_02.jpg);
width: 570px;
background-repeat: repeat-y;
text-align: left;
margin-left: auto;
margin-right: auto;
}
#header{
background-image: url(images/bg_01.jpg);
height: 419px;
width: 570px;
background-repeat: no-repeat;
}
#content{
float: left;
display: inline;
width: 330px;
margin-left: 15px;
color: #61725C;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
}
#contentright{
float: right;
display: inline;
margin-right: 12px;
width: 198px;
color: #282F26;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
}
#footer{
clear: both;
background-image: url(images/bg_03.jpg);
height: 51px;
width: 570px;
background-repeat: no-repeat;
}
.divTitle{
border-bottom:1px solid #adbb99;
color: #adbb99;
text-transform: uppercase;
font-weight: bold;
font-size: 10px;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
letter-spacing: 2px;
}
.itemtitle, .singlet, h3{
border-bottom: 1px solid #48503C;
color: #EEF0EC;
background-color: #879574;
padding: 2px;
text-transform: capitalize;
font-weight: bold;
font-size: 10px;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
letter-spacing: 2px;
}
textarea{
padding: 2px;
background-color: #A8B199;
border: 1px solid #667056;
color: #1C211A;
font-size: 10px;
font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;
width:80%;
}
input,select{
padding: 2px;
background-color: #A8B199;
border: 1px solid #667056;
color: #1C211A;
font-size: 10px;
font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;
margin: 2px 2px 5px 2px;
}
.divTitle3, #comments, #postcomment{
background-color: #96A287;
border-bottom: 1px solid #717E61;
color: #E5E8E1;
text-transform: lowercase;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
font-weight: bold;
padding: 2px;
}
#comments a:link, #comments a:visited, #postcomment a:link, #postcomment a:visited, h3 a:link, h3 a:visited{
text-decoration: none;
border-bottom: none;
}
#comments a:hover, #postcomment a:hover, h3 a:hover{
text-decoration: none;
border-bottom: none;
}
ul{
list-style-image: url(images/ul.gif);
padding-left: 12px;
margin-left: 10px;
line-height: 15px;
color: #58634C;
}
a:link, a:visited{
color: #910808;
text-decoration: underline;
border-bottom: 1px solid #2D5229;
padding-bottom: 1px;
}
a:hover{
color: #541212;
text-decoration: underline;
border-bottom: 1px solid #2D5229;
padding-bottom: 1px;
}
h2,caption{
font-weight: bold;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
}
.singolocommento{
border: 1px solid #879574;
background-color: #E8E9E4;
padding: 5px;
margin-bottom: 15px;
}
blockquote{
background-color: #E7E0D8;
border-bottom:1px solid #A31008;
border-top: 1px solid #A31008;
padding: 5px;
color: #6C0A05;
font-style: italic;
font-family: Georgia, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
}
#wp-calendar{
width: 180px;
margin-bottom: 10px;
padding: 3px;
text-align: center;
border: 1px solid #B7BFAC;
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
color: #677258;
}
td{
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 10px;
color: #677258;
}
th{
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: 9px;
color: #870909;
font-weight: bold;
}
#wp-calendar #today{
background-color: #AEB7A1;
border: 1px solid #707C5F;