Take I-83 North to Timonium Road East. Turn right at the 2nd traffic light, which is W. Aylesbury Rd. This is at the shopping center with REI and Superfresh. Continue past the shopping center, and follow as the road begins to curve. Susquehanna Yoga is on the left, with a yellow awning out front, and some prayer flags. If you find that you come to the end of Aylesbury at York Rd, you've gone too far, turn around and come back. It's not the clearest, best lit building after dark, but you should find it - it will probably be the only place on that side of the street with much traffic in the evening!
I found the directions on Mapquest, but with just 12 W. Aylesbury Rd - that is correct, if you want to print door to door directions.