The CrossDresser program is free but many of the current model licenses need to be purchased separately. Some older models can be downloaded for free though. Wardrobe Wizard came as a standard add-in with Poser until recently, I don't know if it is currently available as a standalone. However, you do need to purchase licenses for different models.

As randym77 posted, simply resizing the outfit does not make it conforming nor will it retain its form if parented to the figure. Conforming clothing needs to be rigged and this is usually from a donor that the clothing is made for. Your only option with Poser 5 is the Cloth Room, but the type of clothing you require is dynamic in nature and typically a prop without rigging.