Thanks for the link, it's much easier for us to help you if you provide one.
If I understand correctly, you're wanting the background graphic for the header div below the menu to fully show, with the menu in between the two header graphics. After looking at your code, the positioning percentages are the cause of it getting cut off. In the code for #rt-header2 on line 25 of style4.css the vertical percentage is set to 120%, meaning it's pushing the image below the div, 100% is where you should set that. If you need the image to go lower, add a height to this div, the number you use there will push it down, like:#rt-header2 {
background: url(../images/backgrounds/style4/header-div.png) 50% 100% repeat-x;
height: 60px;
}
Change the height to suit your needs. Hope that helps.