So, we've been solidly "okay" for about a week on all of our categories in Area 51. What's the process to get out? Does SE evaluate on their own? Do we just wait? I don't know.
I asked a similar question some time ago, and got a great explanation from Grace Note about the graduation process. Basically, it's a long process, and many sites have been ready to graduate for a long time (read: months and years), but because one of the requirements is that someone at SE creates the final design for the site, and there are many beta sites waiting for design, it's going to take some time.
Not to bring down your hopes (I'm eager to see JSE graduate from public beta too), but many SE sites have been in beta for years. Just take a look at the current stats for Code Review, with 1399 days in beta):
As @DavidFritsch pointed out, as long as the site keeps growing the only difference between a public beta and a graduated site is the layout.