if you have margalla running on petrol, get CNG kit installed it will become hybrid fuel car. cost will be under Rs. 50000
but you want to convert it to an electric hybrid. you need to get approval from Pak Suzuki, WAPDA, PIQS, FBR, ENERCON, & TOYOTA. submit a copy of your plan with details of engine , batteries and certification for road worthiness, 3 copies each to above departments before doing the modification to a car which is no longer produced by Suzuki. after approvals you shall find a workshop equipped with technical instruments to help you do the swap.
surely it will have some financial aspects but am sure you know your project and willing to invest such funds for such a remarkable DIY.