need to shorten post content

Hi

I’m trying to shorten up some content that is linked to the home page on my site, via this code:

<div class="homeBox">
	<h2><?php echo $box1->post_title?></h2>
	<?php echo apply_filters('the_content', $box1->post_content);?>
	<a href="<?php echo get_option('boldy_home_box1_link')?>"><strong>Read more &raquo;</strong></a>
</div>

It displays the hole content I only want a short paragraph.

I’ve tried changing ‘the_content’ to “post_excerpt” and so on but it seemed to have no effect or it wiped it out completely… any ideas?

Thanks