1. Yes, you should be able to export your Excel data into a CSV file and import it to your database -- assuming you have any kind of modern database. It's not very hard with Access. On the opposite extreme, if you have Oracle, you will need help from your DBA. Either way, someone in your IT department should be able to do this in minutes.
2. If you want to replace that current database application, there are a couple of ways to go. Autodesk FMDesktop will import DWF files from AutoCAD Architecture. Then you would need to attribute the spaces. The Facility Manager application has a report similar to what you describe, but since everyone does that allocation slightly differently, you might need to customize the report. This is not too hard if you know how to deal with Access reports.The advantage here is that you get a nice environment for producing reports with colored floor plans and so on for not much money.
3. Another approach would be to write your own database report. Again, Access is probably the easiest way to do it, but you might need some consulting help since the report you describe requires some nested queries and intermediate results. I'm not sure if you can move the polygon areas directly to the database from AutoCAD Architecture. If not, you would need a copy of Autodesk Map 3D to do connect directly. Or you can continue to use the Schedule to Excel to database method you described first.
Sorry for the long answer.
Mark Evans
Senior Product Manager
AEC Division, Simulation Product Line
Autodesk, Inc.