Paginated posts on a static page?

Wow, the subject sounds complicated so I’ll quickly explain what I need help with:

I’m trying use WP as a CMS and I need static page to display posts from one category (think “latest work” on a portfolio page -> posts in “Work” category). I set it up to display latest 6 posts but I would like to have a “previous” and “next” buttons/links if there is more than 6 posts in this category. Sounds fairly easy for an actual blog but for some reason I can’t make it work on a static page.

<div id="portfolio">

                      <?php
         $breaking_cat = "1";
         $breaking_num = "6";
         ?>

         <?php $projects = new WP_Query('showposts='.$breaking_num.'&cat='.$breaking_cat.''); ?>

         <?php while ($projects->have_posts()) : $projects->the_post(); ?>

            <div class="item">

               <img src="<?php echo get_post_meta($post->ID, 'project_thumb',true) ?>" alt="<?php the_title(); ?>" />
               <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
               <?php the_content(); ?>

            </div><!-- end item -->

            <?php endwhile; ?>

         </div><!-- end portfolio -->

         <div id="folioNav">

            <span id="previous" class="png_bg"><?php previous_post_link('Previous') ?></span>
            <span id="next" class="png_bg"><?php next_post_link('Next'); ?></span>

         </div><!-- end folioNav -->

Any ideas on what I’m doing wrong would be appreciated. I’m fairly new to WordPress and have no other PHP experience so I gave up trying to figure it out myself :/

Thanks in advance!
Justine