Sony Ericsson — Faulty Mobile Piece

I purchased G502 model on 16/02/09...Within 5 months of purchasing i have replaced display, speaker, headphones, rf board n now the battery.The cell was hardly with me in these 5 months not even for 35 days rest of the days it was with the service center...Now i want replacement for the cell as there', again some problems with display n stuff.Also what if the same problem continues even after the warranty gets over...
I have wasted more then 1000 rupees on petrol and calls i also want a compensation for it...