This March I had a dismal diagnostic score of 146.

I have taken all oft he latest PT's (50's) and most of those in the 40's and 30's. I have done many problems in my Princeton Review book from recent PT's as well. How would you all suggest I study for the next 3 months? Would you all advise doing the VERY old PT's? Also, would anyone advise re-taking PT's? I have heard good things about the power score bibles. Is that a good place to start?
Also, out of curiosity where do yall think I could I get in with my score now? I have a 3.9 and I am an AA male. I don't plan on the 158 being my score but I would kind of like to know where I stand as of right now. Also, with a 166 where do you think I could get into?
Thanks!