Visa renewal is based on 365days, but at the time when you renew your licence it will surely be valid for less than 1 year for sure, which means everyone's will get 2yrs instead of 5yrs? Except those with visa more than a year?
For the car to go thru, no problem for personal registered car, you just need to fill in the paperwork and get insurance, one of the shops before the border crossing will do it for a fee. Ask them to explain the process to you. On your visa to exit and return....someone in this visa group will advise.