I'd suggest adding a search bar for the website on the right top. Websites commonly have searchbars on the right top and it's smart to put it in the same position as people expect it.
Currently the search option is in the menu on the left which can be hard to locate as it looks like any other menu item, it doesn't draw any special attention to it indicating that it is a search bar. Some examples of websites that have searchbars on the right top:
www.joomla.org/
forum.joomla.org/ (PHPBB)
www.mybb.com/
www.simplemachines.org/community/index.php
facepunch.com/
developer.paypal.com/
twitter.com/
It's good for the user experience (UX) to put elements in places where people expect it, and since it's been quite a standard that search bars are on the right top, I think this could improve the usability of your website.