In most states if you have completed the 75 hours of initial training to become a trainee appraiser, you will be required to take an additional 75 hours to upgrade your license and become a licensed residential appraiser.
Depending on your study habits and study goals 75-hours could be completed as quickly as a couple weeks studying 8 hours/day. Most students spend an average of 1 hour/day studying. At that rate you could complete your courses in about 2 1/2 months.
You can review your state requirements and which order the AQB recommends that you take courses HERE.