Installing Featured Content Gallery plug-in

Hi i wanted to install the Featured Content Gallery plug-in but i dont know where i have to put the code:”<?php include (ABSPATH . ‘/wp-content/plugins/content-gallery/gallery.php’); ?>”

Please tell me where, i gave you my index.php where i think i have to put it(The theme is revolution church wordpress)

<?php get_header(); ?>

<div id=”content”>

<div id=”contentleft”>

<div class=”postarea”>

<?php include(TEMPLATEPATH.”/breadcrumb.php”);?>

<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<h1><?php the_title(); ?></h1>

<div class=”date”>

<div class=”dateleft”>
<p><span class=”time”><?php the_time(‘F j, Y’); ?></span> by <?php the_author_posts_link(); ?>  <?php edit_post_link(‘(Edit)’, ”, ”); ?>
Filed under <?php the_category(‘, ‘) ?></p>
</div>

<div class=”dateright”>
<p><span class=”icomment”>#respond”><?php comments_number(‘Leave a Comment’, ‘1 Comment’, ‘% Comments’); ?></span></p>
</div>

</div>

<div style=”clear:both;”></div>

<?php the_content(__(‘Read more’));?><div style=”clear:both;”></div>

<div class=”postmeta”>
<p><span class=”tags”>Tags: <?php the_tags(”) ?></span></p>
</div>

<!–
<?php trackback_rdf(); ?>
–>

<?php endwhile; else: ?>

<p><?php _e(‘Sorry, no posts matched your criteria.’); ?></p><?php endif; ?>

</div>

<div class=”adsense-post”>

<!–To activate your Google AdSense ad, go to your WP dashboard and go to Appearance -> Revolution Church Options and enter your Google Adsense Code.–>

<?php $adsense_468 = get_option(‘revchurch_adsense_468’); echo stripslashes($adsense_468); ?>

</div>

<div class=”comments”>

<?php comments_template(”,true); ?>

</div>

</div>

<?php include(TEMPLATEPATH.”/sidebar.php”);?>

</div>

<!– The main column ends –>

<?php get_footer(); ?>

Thank for your help