added hyperlink to header now buttons on top of header are overlapping the header

Hi!

I added a hyperlink to the header of this page that points to the home page.
http://www.topsecurityinc.com/about-us.asp
Now the top navigation buttons are overlapping the bottom of the header.
I tried adjusting the height of the buttons in the stylesheet, but it had no effect.
Then I tried adding to the margin setting in the .topnav-wrap class and the bar immediately
was pushed under the main content section.
I am pretty sure this is the section of the stylesheet that needs to be modified.

.navwrapper{width:829px;}
.topnav{width:829px;margin-left:9px;margin-bottom:0;height:42px;padding-left:5px;min-width:518px;}
.topnav-wrap *{margin:0;padding:0;}
.topnav-wrap{width:829px;margin-left:9px;height:42px;padding-left:5px;}
.topnav-wrap a{text-decoration:none;}
.topnav-wrap ul{list-style:none;}
.topnav-wrap p{margin:15px 0;}

Maybe I need to push the navigation bar down a few pixels?
Any specific code modifications would be appreciated.