Hi Jimmy,
The first thing to do here is familiarize yourself with the process for overriding and customizing templates as described in our Themer’s Guide. From there, create a custom eddtickets/tickets.php template within your theme.
The idea would be to add a little code, possibly right after this existing section:
echo "<td class='tickets_description'>";
echo $ticket->description;
echo "</td>";
Something like this ought to do the trick:
$limit = get_post_meta( $product->ID, '_stock', true );
$sold = edd_get_download_sales_stats( $product->ID );
$remaining = $limit - $sold;
echo "<td class='tickets_sales'>";
echo "$remaining left! (sold $sold of $limit)";
echo "</td>";
Would that work for you here?