Custom Reports in Reports not available??

2 questions... 1. I just figured out how to download the reports available. I just realized that when I go to reports in store operations manager, the custom reports option is not available. Is there a reason for this? How can I fix this? 2. I really need to do a report on customers. I need to know how much money a list of customers has spent between certain dates. I can't seem to get any of my report options to let me do all of those things at once. EX. customers that spent greater than or equal to $50 between 11/1/06 and 12/31/06 and to have it list the total sales for that time frame. PLEASE HELP if you can! I am going insane trying to figure this out. THANKS!!