Great, glad to hear you are making progress.
So we have the xls file uploaded to the server and stored away ok right?
Great, so then we need a way to open the xls file and parse its data, and commit it to a database for storage.
As some pointers:
You need to understand what a ADO.NET Data Provider is (specifically the Sql Server flavour as that is that you will be working with).
Now personally, I have not done much xls parsing with .NET, my first instinct would be to grab the PIA's and open up the xls file using the Excel DOM but, I am pretty sure you need Office installed on the server, and I am not too sure what the performance/reliability would be like in that environment (only done it via Windows apps). Other than that, you would need to understand the file structure to be able to extract the data from it.
Perhaps someone else could offer more insight there?
But yes, definately need to get your head round ADO.NET and the Sql Server Data Provider. If you have any queries with these, then please ask :)