You realize you contradicted yourself in back-to-back sentences...
While below 'average' matriculant, 30 is absolutely fine. Granted they are exceptions and not the rule, I personally know applicants who have gotten into programs as competitive as Case, Mayo, and some top tier privates with a 30. It's all about how you, your application, and your letter writers sell you to committees.
I'm not trying to butter you up and make you feel good. I'm just trying to make sure you stay proactive. The worst thing to happen is you fall into complacency and start missing deadlines the next application cycle. Granted it's far away, I've seen it happen. Hope for the best, but continue to 'beef up' your application, especially if there are any spots that are 'average' or less.
Some already have or will conclude by the turn of the year. Most conclude in late winter, early spring (think February, March). A few go as late as April. Many schools schedule a month in advance, so they are filling up January and February interview slots at this point.
As for schools, if you were complete in August, chances are they have reviewed your application and not decided to interview you at this point. Since the cycle gets consistently more competitive, chances are you will not be reconsidered for an interview if that is the case. However, that doesn't make it impossible, and there are certainly people who have interviewed once late in the cycle and achieved admission. Again, they're the exception.
Main thing is, with all this in mind, you stay positive and don't get too preoccupied with it. If you must stay proactive (you're a premed, assumable Type A, so probably) and you are really interested in a particular school that hasn't talked to you yet, and they are receptive, go ahead and write and send a letter of interest. It can't hurt.