New design for a Magento shop

I have a Magento shop ( [login to view URL] ). I am satisfied with the structure and layout but I would like to get new design (colours, CSS etc) to the web site. The project is: creating new design for the shop and after the new design is accepted and confirmed by me the changes also have to be put live. The shop is active and functional so any changes to the shop must be made with extreme caution and well planned ahead. Only bid if you are sure you can finish the project 100% on time.