I believe your only issue is reading from the excel file, rest I think you can do on your own. Try these steps:
1. Read excel to the grid. This link
will be of help.
2. Edit data in your grid.
3. Once you are done with editing, you can take out the datasource of the grid(which was set in step 1) as DataTable.
4. Now this DataTable can be updated to the database. Try Google
Hope this help.