Prague to Wroclaw is 282 km and would take about 4 hours by car and cost about �25 in petrol.
Check Via Michelin here:
http://www.viamichelin.com/viamichelin/int/tpl /hme/MaHomePage.htm
If there are no direct flights from Prague to Wroclaw, doing the trip by car would surely be quickest and cheapest (unless you need to rent a car).
Four hours may seem a long time, but consider how long the trip would take door to door if you flew.
You should be able to check the train possibilities here:
http://www.bahn.de/p/view/index.shtml