Dubai-Salalah via Mezyad Border Post

Planning to visit Salalah with my own car for a total Oman stay duration of 9 days. As per google I need to enter Oman through Mezyad Border Post. But want to clarify few points:

1. My current car insurer is charging "AED325 + VAT = 30 days (1 month)" for Orange card**.** Should I purchase with my insurer or better to get at border ?
2. If I need to get Orange card at border, at which point I have to purchase like before or after exiting UAE, and is there any specific building for the car insurance process, approx price and time to get it ?

Thanks.