Dynamic parent page highligtning

Hi!

I want to highlight my parent and grandparent pages, when on a child page.
And I don’t know how. Please help me, I have looked at other posts and found this piece of code :

<?php>
function has_parent($post, $post_id) {
  if ($post->ID == $post_id) return true;
  else if ($post->post_parent == 0) return false;
  else return has_parent(get_post($post->post_parent),$post_id);
}
?>

<?php global $wp_query; if( has_parent($wp_query->post), 3) :?>
<?php endif; ?>

But I don’t know how I’m supposed to write to make it work!
Thank you in advance

I have two menus:

<div id="topNav">
	<div id="topNav_topShadow"></div>
    <div id="topNav_content">

    	<ul id="menu">
                       <li class="urskog"<?php
                if (is_page('urskog'))
                {
                echo " id=\"current\"";
                }?>>
                <a>/urskog">Urskog</a>

             <li class="products"<?php
                if(is_page('products'))
                {
                echo " id=\"current\"";
                }?>>
                <a>/products/lov/walnut">Products</a>

              <li class="press"<?php
                if(is_page('press'))
                {
                echo " id=\"current\"";
                }?>>
                <a>/press">Press</a>

             <li class="contact"<?php
                if(is_page('contact'))
                {
                echo " id=\"current\"";
                }?>>
                <a>/contact">Kontakt</a>

        <li class="separator">

My second menu:

<ul>
				<li class="mainNav_lov"<?php 

					if (is_page('lov')) 

					{
					echo " id=\"current2\"";

					}?>>

					<a>/products/lov/walnut">Lov</a>

				<li class="mainNav_miniLov"<?php 

					if (is_page('minilov')) 

					{

					echo " id=\"current2\"";

					}?>>

					<a>/products/minilov/walnut">Mini Lov</a>

				<li class="mainNav_pinne"<?php 

					if (is_page('pinne')) 

					{

					echo " id=\"current2\"";

					}?>>

					<a>/products/pinne/walnut">Pinne</a>

				<li class="mainNav_pokus"<?php 

					if (is_page('pokus')) 

					{

					echo " id=\"current2\"";

					}?>>

					<a>/products/pokus/walnut">Pokus</a>

				<li class="mainNav_kil"<?php 

					if (is_page('kil')) 

					{

					echo " id=\"current2\"";

					}?>>

					<a>/products/kil">Kil</a>

				<li class="mainNav_skate"<?php 

					if (is_page('skate')) 

					{

					echo " id=\"current2\"";

					}?>>

					<a>/products/skate/walnut">Skate</a>

			<li class="mainNav_drivved"<?php 	

				if (is_page('drivved'))

				{
				echo " id=\"current2\"";

				}?>>	

				<a href="<?php bloginfo('url') ?>/products/drivved">Drivved</a>

			</li>
                                <li class="mainNav_separator">

</ul>