Hi Soumya,

600 is a great baseline score, and a 140-point increase in 2 months is definitely possible. You can reschedule your test up to 1 week before your test, so you don't need to make any rescheduling decisions just yet. I typically suggest that students achieve their target score on at least 2 practices tests before they take the official test.

I should point out that everyone struggles with Data Sufficiency (DS) questions at first. This question type is totally unique to the GMAT, so it's foreign territory. Once you become more familiar with this question type, you should expect a significant score increase. If you're looking for some extra DS resources, we have a free set of videos that cover everything you need to know: https://www.gmatprepnow.com/module/gmat-data-sufficiency

Also, given that you have 2 months to prepare, you might consider signing up for Beat The GMAT's free 60-Day Study Guide (https://www.beatthegmat.com/mba/gmat-guide).
Each day, you will receive an email with a series of learning activities that guide you, step-by-step, from Day 1 to test day. This will ensure that you will cover everything that the GMAT tests.

Here's an outline of all 60 emails: https://www.beatthegmat.com/mba/gmat-guide-outline

Cheers,
Brent