What you are doing is terrific. Hard biking (I'm assuming it's pretty hilly and the rides are challenging) will build up your quads and calves.
It's not weight training of course. Most of your legs are getting a good workout. When you hit the gym, you would benefit from some leg curls. Upper body workouts are essential. And building abs is terrific for biking.
Remember this about working out in another city. NO ONE will ever see you again! It's nothing to be embarrassed about. You are actually out there doing something for yourself.