Image category word count (more)

Iam looking for a plugin or hack that does the following things:

– Automatically adds a <!–more–> afther a specified ammount of words or one paragraph. Not only for the frontpage but also for the categorypages, searchresults and so on. AND
– Automatically adds an image based on the category a certain post is posted into. Every category has it’s own specific image. It needs to load next to the content of the post on the frontpage. An example of what i mean is located here: http://hacktopia.org/
So really an image next to the postcontent, not one replacing the category title.
If more categories are selected it needs to show only one image, preferable the last category selected.

I unfortunatelly don’t PHP skills, i do know HTML and CSS. If someone has a hack please also explain what i need to change in what file.

I use wp 1.52