I agree with Italy, especially Tuscany and or Umbria. Within your budget, you could easily rent a villa or apartment in the countryside for a week and rent a car to visit many of the magnificent hill towns. The most expensive thing is the gasoline. Food is relatively inexpensive if you eat in the towns and stay away from the tourist traps. Also, renting a place allows you to have some meals (we especially liked having breakfast) at home. To get an idea of the cost of rentals in the area, check out http://www.theparkercompany.com. We rented through them and were quite pleased.

Lisa in Chicago