Create a Custom Wordpress Template from an existing site

Create a Wordpress Template for an existing website. The website is currently using PHP, MySQL and CSS. It consist of 7 page categories where the page content is stored in MySQL and delivered through PHP. I would like to modernise the backend of the site using wordpress. No design work is required, the existing design, look and feel of the current site should be retained - an all existing CSS can be reused in the wordpress template as needed. I can provide the existing PHP code, MySQL and CSS. What I need specifically is: -A new wordpress template that matches the current look of the site. -All pages can be update in Wordpress -There will need to be some template pages that can display a summary of posts based on the category. -There will need to be a variable section, or Plugin to hold variables, for header/footer information - such as telephone number, etc.