You do know the Challenge Log resets every Tuesday, so if you've completed it already you can do it again? The Hunting Log on the other hand, isn't repeatable, which I guess is what you're confusing it with.

Otherwise Battlecraft leves at the Observatorium in Coerthas, FATEs in that general area, or if you're having trouble, FATEs and leves at Wineport in Eastern La Noscea are an alternative.