For the record, this manual has factors for different ecomonic regions, this is a close estimate for the job.
Your job is for converting one half of a double into a living space, my only example is to convert a double into a complete living space, so you might want to take half of this project's costs.
LEVEL OF DIFICULTY: this is a major undertaking, but since the area is covered and close, it can be done in stages which is good. Many of the tasks can be accomplished by beginners. Your area of expertise are in windows, doors, framing and other areas.
Material and labor for a 22 x 22 garage is $15,734. So half of that is roughly $7.5K.