Migración de joomla 1.5 a drupal 7

I generally find that in the process of migrating a website to a new system or framework, importing and moving data is the most fraught, frustrating and troublesome part of the process. If you're moving content from a vanilla installation to another vanilla installation you might be in luck, but really, what are the chances of that?I long ago decided to merge a joomla 1.5 site I have into a new site I was setting up in drupal 7, the content that needed to come across was: