From start to Finish:- 14-15 months (If you get lucky on PERM)...With PERM AUDIT add one more year.

@infoseeker - Just realized when I looked in Visa Bulletin to answer your question. So Sis, EB3 ROW is running at 15JUL15. Go get it. Like @OZAR mentioned - that could be the timeline you'd be green. Good Luck!

But if you have not filed the PERM then obviously your Priority Date will NOT be 15JUL15 but still you could get it almost at an EB2 rate.

Reference:
http://travel.state.gov/content/visas/english/law-and-policy/bulletin/2015/visa-bulletin-for-august-2015.html

How about Eb2 with perm approved

If you are EB2 ROW (obviously), you can file 140 and 485 concurrently. With a premium processing for 140 (without an RFE) you should know your 140 status in almost 3 weeks time. If you file 485 concurrently, with Biometrics and all, a happy path scenario would make you green in not more than 4 to 6 months. Also depends on whether your processing center is Texas or Nebraska? Historically, Nebraska is faster. In 2014, my ex-roommate's EB2 ROW 485 got approved in about 90 days after PERM approval. Good luck my friend.

Reference:
http://www.uscis.gov/green-card/green-card-through-job/previous-pending-employment-based-i-485-inventory/pending-employment-based-i-485-inventory

http://www.trackitt.com/usa-discussion-forums/i485-eb/1463216525/eb2-row-nebraska-let-s-keep-track