Sharing info frm 1 Excel to 3 new excel

I prepare 3 monthly Excel reports that is cummulative from 1998 with data from one Excel file for the specific month. I have been cutting a page but the process takes at least 8 hours to complete — lots of data. How do I simplyfy this and programmy monthly reports to automaticaly update the information from the 1 file. Each new report takes only a certain potion of the data from the 1 file. Help – I am in cut and paste hell. Thanks for any help you can give.

Elaine