Help with drop-down menus

Hey, could someone help me create a horizontal navigation drop-down menu for the Gracia theme? The following is in my header.php code:

<div class="navcontainer">
		<?php
                    if(function_exists('wp_nav_menu')) {
                        wp_nav_menu( 'depth=1&theme_location=menu_2&menu_id=nav&container=&fallback_cb=menu_2_default');
                    } else {
                        menu_2_default();
                    }

                    function menu_2_default()
                    {
                        ?>
                        <ul id="nav">
    						<li <?php if(is_home()) { echo ' class="current-cat" '; } ?>><a href="<?php bloginfo('url'); ?>">Home</a></li><!--
    						<?php wp_list_pages('depth=2&hide_empty=0&orderby=name&order=ASC&title_li=' ); ?>-->
    					</ul>
                        <?php
                    }
                ?>		

				</div>

The second part is commented out because it reveals ALL of the pages on the website. However, I don’t want it to do that. There are parent and children (and even grandchildren) pages and I want to create drop-down menus that reflects that hierarchy. Please help!

I’ve created a custom menu that shows the hierarchy, so is there a way to call that custom menu (which is called “Navigation”)?