Should I convert my GPA to the US 0-4 Scale in the Common App Section Grades?

[skieurope]

Should I convert my GPA to the US 0-4 Scale in the Common App Section Grades?

No.

So if I have a GPA of 1 in Austria, should I put 1.0 or 4.0 as my unweighted GPA for the college application?

1.0

You should assume that the colleges to which you are applying have admissions officers who are well-versed in the grading systems in various countries.