Add a vertical menu?

[chaoske]

I'd like to buy this theme from templatemonster: http://livedemo00.template-help.com/prestashop_33531/category.php?id_category=3

 

But we'd like to add a vertical menu on the left containing the categories.

 

Example of the categories on the top left: http://www.doopsuikerlouislouise.be/webwinkel/25-doopsuiker-camille

 

Any help would be greatly appreciated :-)