Search bar in main menu
Here is one approach:


Start by adding a new region to the theme's .info file:

regions[navigation] = Navigation
Next, render the region. Put the code below in page.tpl.php either just before or just after the &lt;/div&gt; in your code above. You may need to experiment a little. 

&lt;?php print render($page['navigation']); ?&gt;
Clear your cache so your site knows that the new region exists.
Next, in Admin -> Structure -> Blocks, place the Search block in the Navigation region. 
Finally, style the search form so it looks the way you want.