Hey Alex,
You haven't read the documentation before updating, right
(I also don't do it sometimes ...
)
It says that you should not go and just install the new version over the old one, but you should first uninstall the old version and then install the new one.
Here is my suggestion: Per default the first settings in the comment config is complete uninstall. It is normally set to 0 or no. This setting will make sure that when uninstalling the component the database tables won't be deleted and you when you install the new component it will pick up those tables.
So, I'm nearly 100% sure that you haven't touched this setting. So you should be safe going and uninstalling the extension. BUT, just to be sure - make a backup before that!
Once you have the database backup, go in your joomla backend and uninstall the component. Once you are raedy, go and install the newest version. Once you do this it should start working like it did before
If you don't think that you can do all this - just provide me with access to your joomla backend, ftp and mysql and I'll do it for you.
Cheers,
Daniel