Hi Nick,
Your best tool for exporting WassUp data in spreadsheet-readable format is "phpMyAdmin".
Your ISP probably provides an interface for phpMyAdmin with MySQL. If not, there is a great plugin called "wp-phpMyAdmin" that adds "phpMyAdmin" as an submenu under the "Manage" admin menu (I have not run it in WP 2.7, so I don't know that submenu location). The plugin automatically connects you to the database and you don't need to remember user name or password. You can get WP-phpMyAdmin at: http://wordpress.designpraxis.at/plugins/wp-phpmyadmin/
If you use phpMyAdmin, here's a quick howto to export WassUp to Excel:
1. In left frame, select your wordpress database
2. Select "wp_wassup" table
3. In right frame, click on "Export"
4. Click on 2nd option, CSV for MS Excel
5. Click Go.
This exports the entire WassUp table to a download file on your PC.
6. Save the download file and import it into Excel.
To breakdown your spreadsheet report by date, the "timestamp" field needs to be converted from a unix timestamp to a date/time value in Excel. Hopefully there is some way for Excel to do that conversion...perhaps by redefining column type??.
Warning: Be extremely careful using "phpMyAdmin"! If you do the wrong thing such as accidentally click on an X icon, you can end up deleting records, an entire table, or corrupting WordPress irreparably.
Good luck.
-Helene.