Hi,
You should move the code:
<div id="hikashop_product_description_main" class="hikashop_product_description_main">
<?php echo JHTML::_('content.prepare',preg_replace('#<hr *id="system-readmore" */>#i','',$this->element->product_description)); ?>
</div>
inside the div hikashop_product_right_part in the file 'show' of the view 'product' via the menu Display->Views.
If the width of the description is too big, the whole right part might go below the image. In that case, you will need to add some CSS like that :
.hikashop_product_right_part { width: 400px; }
in the front end CSS that you can edit via the Display tab of the configuration.