For anyone who want to do this in future, these are the steps I took:
Removed from product/quantity.php
echo '<span class="hikashop_product_stock_count">'.JText::sprintf('X_ITEMS_IN_STOCK',$this->row->product_quantity).'<br/></span>';
if($config->get('button_style','normal')=='css'){
echo '<br />';
}
Added to
product/listing_price.php
After:
echo JText::_('PRICE_END');
Add:
echo '<br/><span class="hikashop_product_stock_count">'.JText::sprintf('X_ITEMS_IN_STOCK',$this->row->product_quantity).'<br/></span>';