There are a few companies out there which sell kits to convert your petrol powered car to electric. These kits will cost around $6,988 and include everything minus the batteries which are pretty expensive, specially if you go for Tesla units which will give you a long range.
Check out this Porsche 911 targa Electric conversion on Youtube to get a better idea of what can be acomplished.
https://www.youtube.com/watch?v=AJLdzRJdKrs