trying to auto populate based of changing a date

I created a workbook with jan thru dec tabs with another tab called daily sales. I would like to know how to when I change the date in my daily sales sheet it will pull the info from the perticular month in the certain boxes. Now one step further As I change the date it has month to date info which I would like it to add the days together as I go further into the month. Email me and I will email spreadsheet. Don;t know if this is possible but worrth a shot. THanks