A 2000 vehicle will use R-134A refridgerant. They make adaptors to inject cans of refridgerant directly in to your system. This is not a good way to do it though. Your system is designed to hold a very specific amount of refridgerant. You should have your system filled by a trained person with the proper guages, scales, etc... to ensure the right amount of refridgerant is used. A good repair person will also use a vacuum pump to determine if there are any leaks in the system. This is all equipment that is very expensive. This makes filling your A/C system impractical to do at home. You should probably bring it in to a service shop.