Sorry to come into this a little late but what I think you want (and completely untested) is:
At the top of your page bring in the wordpress 'header file' (change the path accordingly). This lets you make use of any WordPress function or template tag.
PHP Code:
<?php require('./wordpress/wp-blog-header.php'); ?>
Add this where you want your list of last five posts.
PHP Code:
<ul><?php wp_get_archives('type=postbypost&limit=5'); ?></ul>
Reference:
Creating a Static Front Page.
Template tags: Wp Get Archives.
Hope this helps.