Need help with updating website

I have an existing site that was built using (don't faint), WebPlus by Serif. If you are not familiar, it is a WYSIWYG software program that has gone belly up. It still works fine, but there is no support and no chance of future updates. My site is over 10 years old and is only used by members of our club, mainly sports related pages charting standings/stats.

I am happy with the site, except with the demise of the software, I have additional steps because they are no longer supported; i.e….

Need help with updating website