Dynamically loading an assembly

Question

I need to dynamically load an assembly. Currently I am working with "Microsoft.Office.Microsoft.Office.Interop.dll". I need to open an excel file and get the sheets and data out of it. Can anyone tell me how can I do it?

 Assembly SampleAssembly = Assembly.Load
             ("Microsoft.Office.Interop.Excel, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c");

            if (SampleAssembly != null)
            {
                Type type = SampleAssembly.GetType("Microsoft.Office.Interop.Excel.ApplicationClass");
                Object AppClass = Activator.CreateInstance(type);

               //How will I get ApplicationClass object and Workbooks objects here?
            }