Let me address the first part of your question on retaking the GMAT. You can certainly retake the GMAT in time to apply for the 2015 application season. Round 1 may be tough depending on how long it may take you to reach your goals but not out of the question but whether 1st or 2nd round you certainly have time to retake and submit.
With regards to the second batch of questions there is no magic bullet when it comes to scoring well on the GMAT. The approach I would recommend for you since you have already taken the official test and multiple practice tests is to 1)target your weaknesses and 2)maximize your strengths. Your verbal in particular area of weakness so i would start there.
General Advice
-Time all of your practice questions, whether you are answering one question at a time or in blocks of 10 or 20 you should be timing all sets to simulate the pace of the real exam
-Spend time on reviewing wrong answers, this is often where the best learnings come from so make sure you are really taking in every lesson learned from wrong answers
-Use flash cards: this is particularly helpful for the vocab section of the GMAT, it is a great way to constantly be prepping whether you are waiting in an elevator or in the restroom the repetition is a great way to let tough concepts and rules sync in
-Consistent prep: create a prep schedule that you adhere to on a weekly basis whether you are reviewing grammar rules in the morning and doing questions at night stick to it. Treat your prep like a job you have to go to every day
Those are just a few helpful tips but it really starts with creating a comprehensive plan and really attacking your weaknesses on a daily basis until they are eliminated