Complex sentence: Clarkson made an effort to obtain from fairs and second hand shops the missing copies for the governor general's study and, when she left the viceregal office in 2005, the complete collection of winning books to date had been amassed.
Split into simpler sentences: Clarkson made an effort to obtain from fairs and second hand shops the missing copies for the governor general's study. When Clarkson left the viceregal office in 2005, the complete collection of winning books to date had been amassed.