Hire a personal trainer at least until you're in the rhythm of going to the gym. Make sure, however, that your trainer is qualified. I would recommend hiring an individual with a degree in Exercise Science, Motor Learning, Applied Physiology, or Personal Training and a national certification from NSCA or ACSM. There are a lot of these trainers, and if you don't want to go to a gym, search for a trainer with these qualifications to train you at home. Any personal trainer you hire should provide you with an assessment and a written exercise program.
-Angela Corcoran, director of education at The Cybex Research Institute