Update failed, now, can I revert?!

Hi folks,

have a bit of a problem with a site I set up for some friends of mine. I should state at the outset that I have NO coding knowledge or experience. I'm pretty much a total greenhorn at all of this.
So, here's what happened. We set it all up on Wordpress 3.2.1, and I can't remember what version of Atathualpa it was (but the site was built about 2 years ago). I showed them how to use it and basically handed it over.
Yesterday they contacted me to say they have tried to update Atahualpa (?! why ?!) and that it had failed and now there were no pages showing although all the content was still visible in the dashboard. I logged in and discovered that we can't update Wordpress on that server and so (I assume) the install of the most recent version of Atahualpa is failing. Not Good.

My questions are:
1. Is it possible to somehow salvage the extensive customisations I had done within ATO?
2. Is it possible to install an older version of Atathualpa?
3. Does anybody have any other suggestions?

Thanks in advance for any advice you guys can give.

The site is at http://isscl.com