for the grade 12 thing as long as you did surds in maths and relativity in physics you pretty much have the equivalent of a grade 12.
I have a friend that went over to the US for a while he said he could not find a company that said they didn't employ foreigners. maybe he didn't try hard enough he wasn't that experienced either
you can give it a shot mate, but there are a lot of aussies trying to do the same thing, if you get to a check flight then you are judged on your skill
also try africa i'm hopeing to head over there the end of this year with a bit of luck, I think the conversions are similar if not easier for the yanks over there