sorry if it comes across as harsh, but I'm with sldsmkd on being honest. A great majority of websites these days are run using CMS or content management systems like wordpress etc. You design a template or theme, and then you can edit pages/posts and they are rendered into the style you defined with the theme/template. They use php or a similiar scripting language and need a database and database server. If you then update/change the theme/template it all changes on the page without you having to edit anything.
Re: Microsoft and browser rendering, IE really shouldn't be your testing browser as 99% of the time it renders differently to the others, not the other way round. A microsoft written program to edit pages is thus going to go about things the wrong way not the right way. As I said above, if you go down the cms route, changing pages is a 5 min job rather than half an hour or more, plus if setup right, anyone can edit pages etc. with the correct user details and a paswword...thus making a site editing program redundant.
You can just install wordpress, pick a theme you like to start and add text and voila a site up and running that believe me would be 100 times better than the current one, and render pretty well across all browsers. With plugins you can then have a mobile site, twitter/facebook whatever integration and go from there...any more questions then ask away...