Daymak Munich Help 500w motor to 1000w

I can't find too much information on the Daymak Munich on the web. I am hoping that someone on here might have some experience. I currently have a 48v 500w motor with 12 amp batteries. I want to get more distance and power out of my bike. What type of 1000w motor would fit my bike and what controller would you suggest? Also is there an electrical schematic for this bike I could get?