Changes in Prestashop Menubar

Hi, I'd like to perform some changes in the main web menu: 1.- in the first place, the search text field only appers when the mouse pointer is over the seach icon; I want the search box to appears fix on the menu bar. 2.- when the webpage is displayed in a little screen (tablet for example) the menu and search buttons are overlapped, I'd like to show each one in one side: one on the left and the other on the right. Find attached two imags illustrating the current situation and the result desired. Thanks