Post Meta statement?

Use an if or switch statement to check the value of the meta, then echo out a different class name based on the value:

<?php
$type = get_post_meta($post['ID'], 'Type', true);

switch ( $type ) {
    case 'Yes':
        $class="type-yes";
        break;
    case 'No':
        $class="type-no";
        break;
    default:
        $class="type-na";
        break;
}
?>

<span class="widget_last <?php echo $class; ?>"><?php echo $type; ?></span>

Now you can style each type with .widget_last.type-yes, .widget_last.type-no, or .widget_last.type-na.