Hi, after reading your project, I have to say it is quite easy. I have the solution for your project which will read and handle any Excel file and exports any data you require to database or external server.
I see you mention to extract some columns from excel and manage its content from external UI, this can easily get done, even thought you would do better if you create all this functionality as an Excel plugin, where you can open your file in Excel and from there (Excel UI) export any data within the active Workbook/Spreadsheet. This integration with Excel is installed in your PC like any other application using an InstallShield installer.
If you allow me, I can send you some screenshots and demos of this type of solution (Excel Functionality Integration [Plugin]) as well as standalone applications with Excel file handling, so you see how your project will look like and how it will work with the Excel application and files. No compromise.
Well, I think that is all. I placed 3 days on my bid, 2 to deliver your solution and one more just in case you need any modification to the final solution.
Regards,
John.-