Help with index page code

Hello on the template i am using i have this code on the index page:

<?php get_header() ?>

<div id="container">
<div id="content">

<?php if (have_posts()) : ?>
<?php query_posts('showposts=5'); ?>
<?php while (have_posts()) : the_post(); ?>
<div class="post" id="custom_frontpage_post">
<h1 class="entry-title"><a>" title="<?php printf(__('Permalink to %s', 'sandbox'), wp_specialchars(get_the_title(), 1)) ?>" rel="bookmark"><?php the_title() ?></a></h1>
<div class="entry-date"><?php the_time('d M, Y'); ?></div>
<div class="entry"><?php the_excerpt(); ?></div>
<div class="readmore"><a>" title="<?php printf(__('Permalink to %s', 'sandbox'), wp_specialchars(get_the_title(), 1)) ?>" rel="bookmark">Read More</a></div>
</div>
<?php endwhile; endif;?>

	</div><!-- #content -->
</div><!-- #container -->
<?php get_sidebar() ?>
<?php get_footer() ?>

With this i can show my most recent 5 posts, but i would like to have a “link” to go to older ones and from older go to recent ones, i have tryed this code:

<div id="nav-below" class="navigation">
				<div class="nav-previous"><?php next_posts_link(__('<span class="meta-nav">&laquo;</span> Older posts', 'sandbox')) ?></div>
				<div class="nav-next"><?php previous_posts_link(__('Newer posts <span class="meta-nav">&raquo;</span>', 'sandbox')) ?></div>
				<div class="clearboth"></div>
			</div>

But when i go to “older posts” it only shows the same 5 again, i think its because of the previous code i posted. Can anyone tell me how to solve this, make 5 posts appear in the first page with excerps and “read more” but also make “older posts” appear if you press the button.

I thank you all in advance for the help.