Share button to custom widget

Hi,

I want to add a share button to a widget I created myself.
On the internet I did not find an answer.

My widget output code is:

// WIDGET CODE GOES HERE
	query_posts( array ( 'post_type' => 'boz_fotowedstrijd', 'orderby' => 'date', 'posts_per_page' => 1 ) );
    if (have_posts()) :
	while (have_posts()) : the_post();
	echo '<div style="position:relative;"><a href="fotos/">'.get_the_post_thumbnail($post_id, 'large-thumb') .'<div class="widget-fotovandeweek">'.get_the_title().' </div></a></div>';
	endwhile;
	endif;
	wp_reset_query();

You can see it on this page http://blikopzeewolde.nl/
In de right sidebar, with the title: DOE MEE AAN DE FOTOWEDSTRIJD BLIK OP HET SEIZOEN.

I look forward to a suggestion.
Thanks.