Doing a full redesign


I have a semi-complex project that is written in all singletons and since I just learned about Design Patterns and am about to embark on a rewrite this is a good time to do the design right from the ground up.

I have an XML file witch 5 separate sections.  Each section can have a new object with some detail, update an existing object even more detail, or update an object's already existing detail.   The last entry in the latest section wins if there are conflicts. 

These objects and their parameters/attributes would then get written to various databases, then collated and used to generate a bunch of word and excel files. 

So I think I have:

Abstract Factory for creating the various objects and their attributes (although I can't see it my head on how this would yet)
DAO or an Object Pool for the Database (probably with an Observer on top of that for debugging)
Command for any job queuing
Singletons for the smaller jobs (graphic file generation, word, excel, etc).

Anyone see anything different, or make any suggestions?