You have a couple of lines of code:
Microsoft.Office.Interop.Excel.Workbook oBook = new Workbook();
Microsoft.Office.Interop.Excel.Worksheet oSheet = new Worksheet();
that you cannot use. They don't work because you're trying to create an instance of an Interface, which is impossible.
You have to have Excel create these objects for you.
Workbook wb = oExcel.Workbooks.Add(System.Reflection.Missing.Value);