Build a Website for Small Accounting Practice

A website already exists, written 2007 by myself with a Microsoft Web Editor. What I need is: 1) have the web site re-designed to fit well on PDAs (Ipad, Iphone, Samsungs, + ...+); 2) very simple architechture, that keeps the colors, sections and contents of existing website 3) content must be easily editable by myself. I want the ability to add contents (text, graphics, pdf file for download, +...+) without asking a web designer to do it for me. BASICALLY WHAT I NEED IS A REFRESH OF MY WEBSITE ADDING CAPABILITY TO ADD NEWS AND CONTENT UPDATES AS WELL AS FILES TO DOWNLOAD. EXISTING WEB SITE CAN BE SEEN HERE (IT IS JUST FIVE PAGES, TAKE TIME TO UNDERSTAND WHAT THE CONTENTS ARE: http://preview.tinyurl.com/gpc78ad=