As someone who develops reporting structures for a living, I'll second that, forget what your inept predeccessor has done and redo it from scratch. Approach it as if it were a brand new request.
Forget the look & feel until you are answering the correct questions ... then the look and feel will be easy.
If you handle the data output (answers) as totally seperate from your presentation (format), then you will find that if either requirement changes, it will be a simple matter to update the code.
Good Luck & ...