how do I add a date to the bottom of a list of dates in excel automatically on a daily basis

how do I add a date to the bottom of a list of dates in excel automatically on a daily basis

I have a list of sequential dates (1/01/2012, 2/01/2012, 3/01/2012 etc) in a column in Excel. I want Excel to check the current date and add that date to the bottom of the range if it isn't there already. I only want this to happen once per day so that there are no redundant entries.
For example:
If the list ends at 2/06/2013 and I open the workbook on 2/06/2013, nothing would happen. However, if I opened the workbook again the next day, on 3/06/2013, then that date would be added to the bottom of the list automatically.
I also have two formulas I need copied into the next two cells of that row. If a date was generated for A20, the formulas would be on B20 and C20. The cell references for year/month/date would need to increment by 1 (as in one row) for every new date entry.
For reference, the first formula is:
=SUMIF('Sheet1'!A:A,DATE(YEAR(A1),MONTH(A1),DAY(A1)),'Sheet1'!C:C)`
And the other formula is similar enough to be redundant for the point of solving this problem.
Thanks in advance.