Magento custom theme installation

I require a magento expert to install a custom theme (i will purchase) to replace my current theme. All i require is the installation and bug fixes to ensure it operates efficiently.

There are around 20,000 products uploaded to the site already, and the site is live. I will require all products, categories, images, image labels, product titles, product descriptions, products meta keywords to remain as they are.

It is important that once started the job is complete within a few hours minimising down time. With the theme there is a 140 page pdf installation document.

my current site is http://safetybox.co.uk with a w-p software theme. Please ask if you need more info.