The old website used to host obsolete mods (for older versions), but this was not included when Twallan moved the website to Wikispaces.
I haven't encountered any sort of archive online, so you're only going to be able to get it if somebody here (or on another forum) happens to have a copy saved.
I've only got the latest version, so unfortunately, I can't help you with that.
You can use the latest version of MC without having pets. What's important is what patch
you're up to, more than which expansions you have installed. Are you on patch 1.29? I doubt you're going to be able to find anyone who has MC for patch 1.22 , which is the earliest patch from Generations.