I have 3 weeks to go for the Step 1 exam and I got a 50% on the USMLE sampler and I get 50's on the Kaplan Q-bank. Am I ready or do I need more time. If I need more time what should be my strategy.

Thanks!

Depends on what you want. Do you want to do your best or just pass? Those practice question are somewhat more difficult than the actual exam, but don't fall into a false sense of security. If I were you, I would spend a few hours each day going over the areas that you were weak. The day before the exam do not study, go to a movie or something. Take your time on test day, use all your time. Good luck!