HP Pavilion G4 1326 TU Laptop
False commitment by HP employee in HP store for selling their product

I have purchased a HP Pavilion G4 1326 TU Laptop from the HP IT WORLD, EXPRESS AVENUE, Shop No : 303, 2nd floor, # 49/50, Whites Road, Royapettah, Chennai - 600002, Ph no - 044-28464489/90 on 29.04.12, invoice no : 298. The employee at the store told me that I will get an extended warranty of 1 more year on this product if I register it by the next day by paying 1133INR more. I purchased the laptop then & there, but I was very upset when next morning they informed me that the offer is not available on that particular product and it was a wrong commitment by them. If I have to extend the warranty for 1 more year, then I have to pay 4, 500INR extra and 6100INR for 2 more years. Kindly suggest me, what I should do now.