"Was machst du Idioten starrte" is using the singular even though "Idioten" is the plural of "Idiot", and then uses the past form where there shouldn't be a past form. The placement of the words is wrong as well, it should be "Was starrt ihr Idioten?"
Translated, this would be "What does you Idiots stared?" DERP.
"Hier haben Sie Ihr Erste-Hilfe jetzt, Dummkopf!" This isn't too wrong actually, the "jetzt" (which means now) doesn't fit in there, but other than that, it's decent.
Translated "Here you have your First-Aid now, Dummkopf!"