Much easier than that, you can just use:

Application.Quit

You need not close the workbook first with this command. If you want to specify whether changes are saved in the workbook, do these first. This will stop the Save Changes? message being displayed.

ActiveWorkbook.Save
Application.Quit

If you don't want to save changes, use:

ActiveWorkbook.Saved = True
Application.Quit

This will make Excel think that the workbook has already been saved so it will not prompt the user.

Good luck,
sugarflux x