Making a website accessable for people with disabilities

Basically I have picked a site with no xhtml, no css, bad aethetics and bad accessability. I need you to write how I can improve it first, the later on I need you to create a replacement site with all of the updates. firstly though are the specs for the writeup of improvements.

I need to prepare a critical review of, as near as possible but not more than, 1,500 words on the chosen site. The review should include a description, text or diagram, of the structure of a representative pages and use this together with screen shots of the code (not included in the word count), to comment on both good and bad aspects of the technical structure and the accessibility and how you feel you can improve on it, showing the revised block structure.