Okay, I understand that you have sold 4 lots of Jan'12 which earned you Rs. 12,300-00 (as per your example) and you have bought 4 lots 4600 put for Rs. 1,000-00 which is deducted from your profit (here we are still not counting loss of Rs.400 towards brokerage).
Now, what will you do when November'11 series expires? Won't you have to buy another 4 lots of 4600 PE for December'11 series to cover your position? And that would cost you premium of around Rs. 50 (I am reducing premium from Rs.56 for time expired and assuming the market will remain where it is now) that would cost more of Rs.10,000-00 for 4 lots of 4600 PE!!!
And ditto for January'12 series!
So, I dont see any profit this way
I hope I have understood you clearly and not put cart before horse!!