Complex sentence: It seems she had run away from home (since she was sought via a newspaper advertisement), but in 1780, she had become known as a fortune-teller, and her clientele quickly came from all walks of society.
Split into simpler sentences: It seems she had run away from home at one point, since she was sought via a newspaper advertisement. In 1780, she is confirmed as a fortune-teller, and her clientele quickly came from all walks of society.