Have you got troubles with your prestashop template after updating to 1.5.4.1 version? There is a quick fix for this issue. For the first, you have to open the themes directory. Open the header.tpl file located in your theme. You've got there something like:

<div id="header_right" class="grid_6 omega">
    {$HOOK_TOP}
</div>

all you have to do is to use grid_9 instead the grid_6:

<div id="header_right" class="grid_9 omega">
    {$HOOK_TOP}
</div>

If you've got troubles with the logo (white space between the menu and top of the page) open the file: themes/your_theme/css/global.css and look for:

#header_logo {
float: left;
display: block;
margin-top: 30px;
}

 change it to:

#header_logo {
position: absolute;
top: 30px;
z-index: 1;
}