Storing in Excel file is not the best idea. The file has to be *LOCKED* for the entire duration of the update as you will have problems if 2 people ever tried to add at the same time.
Better would be an Access database.
Even better would be a MySQL or SQL Server database.
A possible alternative would be to add to the end of a ".CSV" file. Excel can open up ".CSV" files and they don't have as many problems as storing to Excel file would.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.