Complex sentence: Her best-known role playing Valeria opposite Arnold Schwarzenegger in 1982's "Conan the Barbarian", after which she appeared in many undistinguished films, although at age 52 she appeared as a dancer in the 2003 film version of "The Singing Detective".
Split into simpler sentences: Her best-known role was playing Valeria opposite Arnold Schwarzenegger in the 1982 film "Conan the Barbarian". Her most recent work was in 2003, when as the age of 52 she appeared as a dancer in the film version of "The Singing Detective".