I think you definitely can improve to the 700 range.
Since you didn't mention what material you are using for your study, I am going to tell you my strategy. It worked for me so hopefully you can have some ideas. Briefly about my situation to explain why I think you can do it: TWO weeks before my real exam, I took the GMATPrep - got 600, and some other tests were in the 550-600 range. I was aiming for 700 so that freaked me out!!! After two week of intensive studying and practicing, I eventually got a 680 on the real one (Q:47, V:37), I was disappointed for not breaking the 700 and wished that I had started differently. But, since you still have one month, I think you just need to pick the right plan.
My problem was I didn't use any prep material at all from the beginning, besides doing problems in the Official Guide. That was a HUGE mistake!! I went through all the questions in the OG without major struggles so I thought I was doing well. I didn't realize that using other materials (Kaplan
, Manhattan, Veritas
...) would give you so much more insights of the topics that are tested. So after reading some posts on this website, I decided to get the Manhattan set. It was a saver!! I only had 2 weeks, so going through all of the books was impossible. But I went through the 5 books for Quant and the SC book. These books are extremely helpful with the way they introduce and explain all important topics that you need to know. Their practice exams are great too, you can familiarize yourself with the time pressure, and how to manage through a good number of hard questions. I did all of them and certainly felt more confident before the exam.
So that was my story. Hope it gives you some ideas. Let me know if you have any questions.