Change existing prestashop theme OR create prestashop theme, Czech & English version

Hello, I would neet to create a theme which can work within Prestashop. I have already found a theme that I am interested in prestashop: [login to view URL] BUT the above mentioned theme does not have all the necessary items I would like to include in the eshop. Thus I am looking for somebody who can upgrade it and improve it so it in the end is more like this: [login to view URL] (not exactly, more like having more options). At the moment I am particularly interested in more options on the left panel similar to the winelibrary (grape varieties, origin, rating of wines, also changes in colour and other minor design changes that we can discuss later on). I have not yet purchased the mentioned prestashop theme. If you feel it would be easier to change the already existing theme OR it is better to build a theme for prestashop from scratch according to my needs please contact me with your offer (time estimate it would take). PLEASE INDICATE WHETHER YOUR PRICE IS FOR CHANGING THE EXISTING THEME OR CREATING A NEW ONE ACCORDING TO MY NEEDS. Thank you. Roman