Questions with extra clause

Hi - where does the question mark go when you are writing a question with a clause? I think the best way to describe the issue is with an example from the old song:

Is it

How much is that doggy in the window - the one with the waggley tail?

or

How much is that doggy in the window? The one with the waggley tail.

or

How much is that doggy in the window? the one with the waggley tail.

The first one seem best to me.

thanks!