chart unique dates with sums

It sounds like a job for a pivot table to me. If you want more help, please post a sample workbook.

First of all, I suggest that you format the data source as an Excel Table. One of the advantages of an Excel Table is that they "know" how big they are and formulas, charts and pivot tables that reference them don't need to be changed when the amount of data in the table changes.

Tables need contiguous headers. so I added some. From now on, you can delete the rows of data from row 2 on down and copy and paste (or append) new data in.

Here is more information on tables: http://www.utteraccess.com/wiki/Tables_in_Excel.

Then it is a matter of constructing a pivot table based on this data. Does the pivot table on sheet 2 look like what you want?