Customizing a template to my website

I have chosen a template and modules for a Joomla 1.7 site. Need some modifications in the template: positioning of menus and modules, articles and the content area. Most content is low size photos (20-40kb), or more detailed photos (100 to 200kb at most) of products. Small pictures will be used in lists of these products and large in pages for product details. So content area can either display a list of products or a product with it's details itself. List will either be normal Joomla list or a slideshow module (chosen by me). Detailed product page will include articles with details (and/or modules) and links to other content in the website. List page may include articles and/or links to other content in the website. Project is these two template pages for products and their lists. Content will be provided and edited in Joomla Administrator (file and page names, languages, SEO etc) by me.