Just a couple things to keep in mind... it's good to pay attention to whether most of the links point to your site with the www. or without. WordPress will redirect to the appropriate page regardless of which you use, but it's better not to have redirects from an SEO perspective if you can help it. So if most of the links point to your site with the www. then when you install WP I would recommend setting up your WP installation to have the www. in the URL by default.
It will be some work to copy all that content into WordPress, but once it's done it'll probably be easier to manage it.
As far as paths to your content, that Redirection plugin @c3mdigital mentioned sounds good though I haven't tried it yet. But how smoothly all that goes may depend somewhat on how organized your current content is. It looks like most of your links are to pages ending in .php. I would assume you'd want to setup your permalinks to end in .php so your links don't all change.
While I haven't tried appending .php to the end of URLs, I would assume it can be done. On the WP Permalinks page located at http://codex.wordpress.org/Using_Permalinks
near the bottom it shows how to have them in in .html, so I assume you could do the same thing with .php.
As you create your pages you'd just have to make sure the permalink is the same as what the page previously was.