Hi,
1. edit the file components/com_hikashop/views/vote/view.html.php and change the line:
$query = 'SELECT count(vote_id) FROM `#__hikashop_vote` WHERE vote_ref_id = '.$hikashop_vote_product_id.' AND vote_type = '.$db->quote('product').'';
to:
$query = 'SELECT count(vote_id) FROM `#__hikashop_vote` WHERE vote_ref_id = '.(int)$hikashop_vote_product_id.' AND vote_type = '.$db->quote('product').'';
and that will fix the problem.
2. For the add to cart button, in the Display tab of the configuration, turn on the option "display add to cart button".