Want to Reverse Chronology of Blog

I read all I could and couldn’t find where to put the code in that you suggested. My index.php file contains the following. Could you tell me where to insert the code snippet you specified in order to make it reverse? I tried several spots with no luck. Thanks!
-R

<?php get_header(); ?>

<div id="content" class="narrowcolumn">

<?php if (have_posts()) : ?>

<?php while (have_posts()) : the_post(); ?>

<div class="post" id="post-<?php the_ID(); ?>">
<h2>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></h2>
<small><?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> --></small>

<div class="entry">
<?php the_content('Read the rest of this entry »'); ?>
</div>

<p class="postmetadata">Posted in <?php the_category(', ') ?> | <?php edit_post_link('Edit', '', ' | '); ?> <?php comments_popup_link('No Comments »', '1 Comment »', '% Comments »'); ?></p>
</div>

<?php endwhile; ?>

<div class="navigation">
<div class="alignleft"><?php next_posts_link('« Previous Entries') ?></div>
<div class="alignright"><?php previous_posts_link('Next Entries »') ?></div>
</div>

<?php else : ?>

<h2 class="center">Not Found</h2>
<p class="center">Sorry, but you are looking for something that isn't here.</p>
<?php include (TEMPLATEPATH . "/searchform.php"); ?>

<?php endif; ?>

</div>

<?php get_sidebar(); ?>

<?php get_footer(); ?>