Marshall - 12:20 am on Jan 28, 2012 (gmt 0)

[div1 | div2 | div3 | div4 .........and I need to fill this gap until here ....... divx]

You can set the background of the navigation division to black. Have divisions 1 through 4 float left and divx float right.

#Nav {
width: 100%
background-color: #000;
}
.NavLeft {
width: 150px; /*example purposes */
float: left;
}
.NavRight {
width: 150px;
float: right;
}

<div id="Nav">
<div class="NavLeft">LINKS</div>
<div class="NavLeft">LINKS</div>
<div class="NavLeft">LINKS</div>
<div class="NavLeft">LINKS</div>
<div class="NavRight">LINKS</div>
</div>
<br style="clear: both;" /> or something to clear after the navigation.

Marshall