Lala, you're too kind!

mrcrowley, if you're not familiar with PHP programming I highly advise that you hire some professional(s) to do this for you.
It looks like a rather complex script and integrating mod_rewrite would take a lot of work.
All I gave here are theoretical examples for those who are writing their own scripts and want to make them SEO friendly.
Modifying an existing script is of course possible but it can also be risky if you're not sure what you're doing.
The code modifications depend on the script itself and editing the source imposes that you are familiar with the way the script works in high detail.