Higher gear needed on '16 Dash


I've got some hills on the commute to work and find myself spinning like a hamster down them after the motor tops out at ~30MPH. Thoughts on the best way to get a higher gear? Anyone install a bigger chainring? Replace the cassette?

Also, I don't find myself shifting out of the highest gear going up those hills. Am I risking overheating the motor? I always downshift for stops to get started again. I use PAS 3 or 4 the whole way. Thanks.