Chris- I found answers in Spanish dict. When it's a question, usted seems to come after the verb. Word order in Spanish is much more flexible than in English but in questions I would tend to follow the verb with usted.
¿Por qué lleva usted gafas de sol?
¿Cómo va usted al trabajo ?
¿Por qué está usted comprando una entrada?
"have you" is in the 'present perfect', which spanish has it's own section on. I think that technically there's a bit of interchangeability there, but just like in english, you would tend to use the "have you"-type sentence for asking if you bought it YET and the "did you"-type sentence to ask the basic yes or no (which in this case seems to be whether or not you just full-on stole the watch :))