What you should have done was designing your website on top of Drupal (or any other CMS).
Not all hope is lost yet :)
PAC architecture separates the
Views from the
Model) more than other architectures (like MVC). This could make the process of implementing your design more easily. You should be able to take your web deisgn and 'push' the data from your CMS into it. I personally never worked with Drupal or Wordpress but theming your own site shouldn't be too hard. I guess you'll need to 'rebuild' your design with drupal's theming guidelines. Read the theming guides HERE.