When to resort to a tutor?

Week -1 of D-day should consist of light review and not much of trying new strategies or learning concepts, including getting a tutor.

Weeks -4 through -2 should consist of practicing CAT exams (timed, including AWA).

You still have a lot of time until your exam so I would focus on primary two things: content and strategy (how to attack problems so when you see them on test day, it becomes second-nature, almost intuitively). It might help for you to develop your own "strategy" with a tutor but you have to ultimately figure out what works for you and what doesn't. To effectively use a tutor, master the core fundamentals and approach a tutor with any specific weaknesses. For example, it's inefficient to approach a tutor to learn about what a prime number is when there are hundreds of resources out there that can answer that question. A tutor should be used to tailor your specific needs and weaknesses. So to answer your question, a tutor might be useful during the last month of your prep.

If you've been studying as much as you have thus far you've probably noticed some things you get incorrect more frequently than others. Once you've pinpointed these troublesome areas then it's time to get a tutor. It'll save you money too because you won't have to review your strong areas.