hi i m us citizen and if i apply petition for my sis who live Pakistan then how long it take in process? can i apply in 2013?

There is no contemplated legislation now that would eliminate the F-4 category for siblings of U.S. citizens at present. So I would imagine that you can petition for your sister in 2013. For that matter, I do not understand why you would not petition for her in 2012 since the category is backed up 12 years at this time. That means that only persons who were applied for in early 2001 are being invited for final interviews for immigration. In your sister's case, probably the earlier the better.