Ignore those numbers; they're supposed to give rough guidelines about when a site is considered viable, but they're based on predictions that were made way back in the early days of Area 51 before anybody really knew what it took to make a site work.
If you want some better rough numbers to gauge our ability to graduate, I'd suggest just looking at the following:
Right now, I'd say that both of those answers are "No". There's been very little growth in our average questions-per-day since we started; even now, in the middle of Ramadan (our busiest time), we're barely reaching the mark:
And as for useful answers, that's far more speculative: What exactly constitutes a "useful" answer? I've expressed my own opinion on that in the past, and quite frankly a lot of the answers I see don't really meet the criteria for what I would consider "useful"; there are far too many posts written by users with barely any grasp of the how the Islamic sciences work or even basic critical evaluation (or even the English language, let's be honest here).
Most of the answers here are barely any better than what you can already get from any number of Islamic fora, or shallow regurgitations of easily-found third-party articles; I'm sure you know how much of a mess those already are. Islam Stack Exchange is trying to improve on what's already out there, not just bring the same mess over to a new venue.
I've said it any number of times before, and I'll keep saying it: What we need to graduate is experts, who not only have the ability to answer existing questions, but are also able to ask new and interesting questions that will attract other experts. There a reason most Islamic fora out there don't tend to attract a lot of actual expert participation, and if the site keeps encouraging low-quality questions, all it'll attract are low-quality users who keep providing low-quality answers.
And that, I can definitely say, is not the path to graduation.