Hi Shraddha91,
To start, since you're interested in at least one highly-competitive School, you would likely find it beneficial to speak with an Admissions Expert about your overall profile and plans. Those Experts should be able to answer your Admissions questions and help define the specific areas of your profile that could use some improvement. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/Many GMATers are unhappy with their initial practice scores, but you really shouldn't be. That 480 is just a measure of your skills right now - and you'll improve on that result over time as you learn more about the content, Tactics and little 'secrets' of the Exam. The OG books are great sources for practice questions, but they're not designed to teach you Tactics, patterns or the little 'secrets' behind the GMAT - for those, you'll need Course-oriented materials.
Statistically-speaking, raising a 480 to the point that you can consistently score 700+ will likely require at least another 3 months of consistent, guided study - and you'll have to make improvements to how you handle BOTH the Quant and Verbal sections. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level. A planned Test Date at the end of December would be a reasonable plan (as that would give you approximately 3 months of additional study time), but you'll have to be focused on learning and practicing the proper Quant and Verbal Tactics needed to earn that type of Score.
1) Are you planning to apply to any other Schools besides INSEAD? When are you planning to apply?
2) Are you planning to take the At-home GMAT or are you planning to take your GMAT at a Test Facility?
3) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich