Hi,
it requires quite some styling and code modifications so I can't provide a complete solution. However, I can point you in the right direction.
In your header.php you'll find
/*
* display the main navigation menu
* check if a description for submenu items was added and change the menu class accordingly
* modify the output in your wordpress admin backend at appearance->menus
*/
echo "<div class='main_menu'>";
$args = array('theme_location'=>'avia', 'fallback_cb' => 'avia_fallback_menu', 'max_columns'=>4);
wp_nav_menu($args);
if(avia_woocommerce_enabled()) echo avia_woocommerce_cart_dropdown();
echo "</div>";
echo "<div class='sub_menu'>";
$args = array('theme_location'=>'avia2', 'fallback_cb' => '');
if(avia_woocommerce_enabled()) $args['fallback_cb'] ='avia_shop_nav';
wp_nav_menu($args);
echo "</div>";
You can work with
if(avia_woocommerce_enabled()) echo avia_woocommerce_cart_dropdown();
and
if(avia_woocommerce_enabled()) $args['fallback_cb'] ='avia_shop_nav';
The first calls the function for your cart and it's icon. The second one calls for the submenu. So - you'd have to merge the first function with the submenu. Both of the functions are written in the woocommerce-config\config.php file.