@Yash,
You don't have to keep waiting until the day your RTR expires, it can be renewed in advance of 3 months from the date of expiry, but never more than that. WPC takes anytime between 15 days to 3 months for the renewal, I obtained mine in the shortest possible time but my buddy didn't (considering we did the paperwork together), What a Bummer! Despite the fact that he submitted all the documents, they wrote to him a telling him that he missed a few documents.
Very unpredictable, isn't it?