70 days left and I'm not sure how to proceed (expert)

That is a great mock CAT score. Keep the good work going on. I would recommend you to appear for another GMAT prep mock CAT and if you score at a similar level, I do not think there is any reason to wait for 70 days. You can reschedule the test and ace it.

Try to drill down into each problem type to ace them.

SC: The questions test various concepts such as S-V agreement, modifiers, parallelism etc. Find out what troubles you. As a general guide line, you can start solving a question by taking the following things in consideration:

1. Find out the subject and the verb
2. See that the S&V agree in number
3. Look out for the modifiers
4. Look out for parallelism
5. Look out for usage of certain words - such as vs like, few vs less etc.

CR: There might be certain types of questions that are troubling you. May be Assumption, may be conclusion, inference etc.
You need to find that out and then practice them
RC: This again can be drilled down into different types of questions and also different topics. See what questions and topics trouble you the most and then practice accordingly.
Quants: Again try to break the questions in topics such as Algebra, Number system (very important), Geometry, PnC etc.

As an addition, start preparing an error log and keep a note of all the mistakes you made and the lessons you learnt from the problems. This will ensure you do not make the same mistake again.