Next and Previous buttons for navigation

I purchased the Nuke theme and added a custom page template using the code from page.php as a framework. The only code I added was a loop to pull 5 posts from category ID 12. I would like to add navigation buttons “Next and Previous” to view the rest of my posts in this category. What code do I need to add?

View an example of custom page layout : http://www.bodys.co.za/diets-recipes/healthy-recipes/
View code of custom page layout : http://www.bodys.co.za/1.jpg or view code below

<?php
/**
 * Template Name: Diets & Recipes
 * Page template for Diets & Recipes 
 *
 * @package WordPress
*/

/**
*   Get Current page object
**/
$page = get_page($post->ID);


/**
*   Get current page id
**/
$current_page_id = '';

if( isset( $page->ID ) ) {
    $current_page_id = $page->ID;
}

$page_style = get_post_meta($current_page_id, 'page_style', true);
$page_sidebar = get_post_meta($current_page_id, 'page_sidebar', true);
if( empty( $page_sidebar ) ) {
    $page_sidebar = 'Page Sidebar';
}

$caption_class = "page_caption";

if( empty( $page_style ) ) {
    $page_style = 'Fullwidth';
}

$add_sidebar = FALSE;
if( $page_style == 'Right Sidebar' ) {
    $add_sidebar = TRUE;
    $page_class = 'sidebar_content';
} else {
    $page_class = 'inner_wrapper';
}

get_header(); 
?>
        <br class="clear"/>

        <!-- Begin content -->
        <div id="content_wrapper"<?php if( !$add_sidebar ) { ?> class="full_page_width"<?php } ?>>

            <div class="inner">

                <?php if( !$add_sidebar ) { ?>
            <?php pp_breadcrumbs(); ?><br/>
            <div class="<?php echo $caption_class; ?>">
                <div class="caption_inner">
                    <h1 class="cufon page_header"><span><?php the_title(); ?></span></h1>
                </div>
            </div>
            <?php } ?>

                <!-- Begin main content -->
                <div class="inner_wrapper">

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

                        <?php if($add_sidebar) { ?>
                            <div class="sidebar_content page_sidebar">
                        <?php } else { ?>
                            <div class="fullwidth">
                        <?php
                            }
                        ?>

                        <?php pp_breadcrumbs(); ?><br/>

            <?php if( $add_sidebar ) { ?>
            <div class="<?php echo $caption_class; ?>">
                <div class="caption_inner">
                    <h1 class="cufon sidebar_page_header"><span><?php the_title(); ?></span></h1>
                </div>
            </div>
            <?php } ?>

                                <?php do_shortcode( the_content() ); ?>

                    <?php
                    $args = array( 'numberposts' => 5, 'category' => 12,);
                    $postslist = get_posts( $args );
                    foreach ( $postslist as $post ) :  setup_postdata( $post ); ?> 
                        <div>
                            <h6>
                            <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
                            </h6>
                                        <div class="post_detail">
                            <?php echo get_the_time( 'F j, Y', get_the_ID() ); ?>
                                            </div>
                            <div class="img_nofade2 alignleft">
                            <a href="<?php the_permalink(); ?>"><?php the_post_thumbnail( 'single-post-thumbnail' ); ?></a>
                            </div>
                            <?php the_excerpt(); ?>
                        </div>

                    <?php endforeach; ?>

                    <br />

                    <div class="clear"></div>

                    </div>

                    <?php endwhile; ?>

                    <?php
                        if($add_sidebar)
                        {
                    ?>
                        <div class="sidebar_wrapper">
                            <br class="clear"/>

                            <div class="sidebar">

                                <div class="content">

                                    <ul class="sidebar_widget">
                                    <?php dynamic_sidebar( $page_sidebar ); ?>
                                    </ul>

                                </div>

                                </div>

                            <br class="clear"/>

                            <div class="sidebar_bottom"></div>
                        </div>
                    <?php
                        }
                    ?>
                </div>

                <!-- End main content -->

                <br class="clear"/><br/>
            </div>

        </div>
        <!-- End content -->

<br class="clear"/>
<?php get_footer(); ?>