To answer your first question, yes you can have 2 save buttons on a form. You can add a Save button simply by adding a button field to the form, and setting it to be a "Save" button.
But what you're wanting methinks is not a save button. You want an approve button, which does a save, and then follows it up with some more code. You'd need to experiment a bit to see the best way of doing this - perhaps when you add another save button you can tell one button from the other? I'm not sure, this isn't something I've tried.
Of course an alternative is to add a checkbox to the form, "approved", and if this is on then handle the code on save differently.
cheers
Bruce