1st off, do not delay. Work on getting the paint off ASAP!
How you need to proceed depends on whether the paint was latex or oil base. Hopefully, it was latex paint... good chance that it was! ..... if so, you may find that just power washing (easy does it with the pressure) and washing vigorously with a sponge and soapy (Dawn Dish Soap) warm water will remove the paint. After removing the paint with Dawn, do wax the car.
By the way here is a very good informational for those that get the yellow or white paint from wet street lines.... Those are a whole different deal. Read here for info on removing such paint: