The eligibility for the national merit scholar? (PSAT)

I am becoming a junior this year, and in October I will be taking a PSAT.
Although people say that PSAT isn’t as momentous as SAT,I’m still putting weigh on PSAT.
BECAUSE, the National Merit scholar.
So, the inquiry here is that how “good” should I perform in PSAT to get the eligibility for the national scholar?
Also, should I must be a citizen or permanent resident in October? Because I’m going to attain the permanent residency in about March of the next year.

Your help would be a crucial aid for me. Thanks!

http://www.studypoint.com/ed/national-merit-scores-nms-qualifying-scores-by-state-class-of-2015/