[Mystique theme] Fixed Background Image

I’m using a Mystique theme, and i’m NEW in using CSS.
I just want to know how make the background image fixed, and i’m having a problem with it especially on the part of the footer… the image seems to end there.

you can check the problem on: thenotebook.zenhonbuph.net

what should i change here?
/* reset spacing */
*{margin:0;padding:0;font-family:"Segoe UI",Calibri,"Myriad Pro",Myriad,"Trebuchet MS",Helvetica,Arial,sans-serif;}

html,body{min-height:100%;}
body{background-image:url(images/bg.png);background-repeat:repeat-x;font-size:13px;font-style:normal;color:#4e4e4e;}

#page{background:transparent url(images/header.jpg) no-repeat top center;}

/* page width. default = fluid @ 780-1190px (max. possible width is 1735px) */
.page-content{width:100%;/* <- do not change this! use max-width to set the page width! */max-width:980px;min-width:780px;margin:0 auto;}

thank you very much.