How do I incorperate broken HTML links into my new PHP website?

I re-did my website. The firm I hired used PHP, while the old website was in HTML. I did a search on Google, and I find several broken links all in HTML and with high PR values. When the website was finished,it was in PHP. My PR went from 1 to 0. How can i pick up the old links, and incorperate them in to the new site without having to rewrite the entire site back to HTML? Thank you for your help!