If your new ISP doesn't allow SSI, you're going to have to go with a different solution altogether. Simply replacing those statements won't work. Perl isn't really made to do what you're looking for, but if you were to write programs that dynamically added the content of your page, you could implement a solution in Perl. Also, there are some Modules that could help out as well such as HTML::Template, but you still have the issue with needing to write a Perl script to render the page.
In lieu of using Perl, I would suggest going with PHP as it is a minimal change for your pages this way. While I won't claim to know vast amounts of knowledge in PHP, I know it can be done by using PHP includes. Put a request in with the PHP forum ( forum434 ) to find out how this is done.
- Rieekan