There is a new direct train connection between Dresden and Wrocław. Trains go 3 times daily and depart from the main train station at 7:32, 13:31 and 17:31. Trains from Wrocław to Dresden depart 7:05 Uhr, 13:05 and 18:05. It takes three-and-a-half hours one way and it costs 39 €. A family ticket costs 59 €, this is a good offer if two adults are travelling together.
So it would be even possible to go for a daytrip to Wrocław, if you would take the morning train there and the evening train back you will have around 7 hours for Wrocław.