If have never tried this myself, but it could just work for you.

You could try to set up your excel sheet as an ODBC data source, and access it with the Uniface ODBC database driver.

The uniface part of this is unusually well documented in the help.

Import EXCEL as a com component signature (/sti {/verbose} /mwr=com PathToTypeLibrary )

Not so well documented but spend some time in the MSDN excel object reference http://msdn.microsoft.com/en-us/library/bb149081(v=office.12).aspx

With the operations you now have exposed in the signature you have total control over EXCEL

I use this all the time (also for WORD & OUTLOOK) - works very well,

Hi there I think it is difficult to do that with out an Excel Processing SDK.There are many advanced component used to edit Excel files and implement page level processing. It can easily add, insert or delete Microsoft Excel worksheets. You can also sort order of your Excel document sheets/pages in C#.NET. Merging or splitting Excel files will not be difficult with this Excel SDK. It also enables you to add image on specified position of an Excel document page or extract page(s) from an Excel file. All these functions can be achieved independently from any third party assembly. You can have a try