Thank you all guys. i had set my mind on the TI 36 XPro of TI30 XS.
Just before the final decision we (she) had to go for shopping, in the meantime i sauntered into my friend's electronic shop. to my surprise i saw a Casio fx-82MS sitting there. (MFG: FEB 2011, MRP: 375). he told me that he had bought it for someone else and they were not interested and if i need it he will give me huge discount
Instantly i decided to buy it. it will be ok for us, and if we do need an upgrade we can go for it and the initial investment is negligible (online price 404 + shipping - flipkart)
Since the purpose is served admins kindly close the thread