Insurance question

fibbi

too busy to check out the insurance agency these days...
maybe you guys could help out...

My original car insurance will expire in July. But I'm trading in my car next week. Can I transfer the same "license plate #" to the new car? If so, that means the insurance still expire in July or start counting from the point when I get the new car?

Would that be much more expensive if I get new license plate now, or use the old one and get a new license number later?

Thanks!