Hello s.vivi, I understand and do feel how you think and feel about your vocabulary. Well, I think only repetition will answer your problem! I'm in the same boat, although I don't have definite date to take the real exam and my study was delayed for certain circumstances, but I wish that I will resume my vocabulary in a while. make an audi of the vocabularies and keep listening to them.This will help you out in case u can not sit and read a book or be in front of the computer for a long time. Make so many quizzez to yourself.
I can not tell you when you will be ready for the real GRE, you have to study hard, don't delay ur exam for a long time, and yet don't take it in a very short time also.
Hope this will help.