The good news is that as my previous commenting system - Haloscan - will be defunct as of Monday, we now have a new commenting system in place: Disqus, which has received excellent reviews.
The bad news is that although Disqus advertised that comments from Haloscan could be migrated over, it has not worked so far. I have a request in to the support team and hopefully will be able to resolve it.
Fortunately, I've been able to save the XML file with all the comments, so I can search them if anyone has specific things they are looking for and I can even share the file with those who are interested, as a last resort if we are unable to get them imported.
The new commenting system required that I change the template, so we have a new look as well.