Complex sentence: Wheaton later gives Penny advice when she wrestles with whether to take a role in the sequel to a low budget horror film she once starred in, and after taking the role finds Wheaton is also appearing in the film.
Split into simpler sentences: Wheaton later gives Penny advice when she wrestles with whether to take a role in the sequel to a low-budget horror film in which she once starred. After taking the role, Penny finds that Wheaton is also appearing in the film.