how can i improve my verbal ...........

I am not an expert to suggest methods to improve verbal, but there is one method that will work for you. In SC, try to find as many errors as possible and that too without timing yourself. That worked for me so I am pretty sure that this method shall help you also.
Moreover, why are you in a hurry to retake the GMAT. First you should try to understand where you made mistakes. If you plan to score atleast a 35-38 in verbal, then being a non-native, its almost impossible under 25-30 days, given the fact that you are also supposed to review your prior errors and continue to take tests.
Lastly, keep practicing and book the date only when you are satisfied with your practice test performance. This will yield you a score more than what you expect.
Good luck and Merry Christmas.