First you said you passed the interview correct?

Otherwise you can not use 1447(b).
I'm a little hesitating to give all my time line for the 'anonymous' nature of the forum. But for relative timing, I filed the lawsuit pro se after about 15 months NC pending. All defendants served the same week and obtained USPS proof which I filed with the court instantly. Contacted AUSA a month later and was told they would try to resolve it without seeing the judge -- he confirmed with me it is for N-400 not AOS first. We filed for two extensions and then luckily my NC got cleared.
It seems you need to read a lot before starting the work. Try absorb as much as you can from this site:
http://immigrationportal.com/showthread.php?t=194681