"Aqui" is not Italian (it's Spanish if I am not mistaken). "Qui" and "qua" (never to be written with an accent!) are almost interchangeable. If anything, "qui" sounds more elegant than "qua" but this is just my opinion. There is actually a slight difference of meaning between the two: "qui" refers to this very specific place whereas "qua" is more general and includes "qui". But even native speakers don't pay attention to the difference.
Agree that "qui" sounds a bit more polite, my Italian friend calls his dogs in using "vieni qua!" FWIW.
I wanted this to be: Where do you work? Could that be a valid translation, too if the intonation was a bit different?
I put 'Are you working here?' and it wouldn't accept that, but I'm sure it's equally correct...