I recently travelled from Sydney to Iceland via the USA. Iceland air or Iceland express runs from many of the major cities in the United States.
A more detailed breakdown of our flights:
Cheap Jetstar to Hawaii - $400
Hawaiian air to mainland (you could go to a connecting city) - $250
Iceland air from NY - $400 (Iceland express is cheaper but more dodgy).
So for $1050 one way you could probably do it with a bit of research. I used Skyscanner. Iceland is beautiful, can't go wrong there. almost 6 years ago