IMPORTING NEW DRUM KITS INTO GARAGEBAND

I am using garageband and an M-Audio Axiom 61 Midi controllor. I recently purchased a sound library of drum kits from www.p5audio.com. Each sound comes as a .wav file. I was assured that they would be compatible with garageband and my controller. I've looked at various websites and links, such as
http://www.xlr8yourmac.com/audio/garageband/garageband_samples.html
but none of them have worked.

I want to be able to control each individual sound from this new sound library just like I control the "Hip Hop Kit" or "Rock Kit" in garageband. I just can't figure out how to add them. Please, if there is any way you could help me that would be great. THANK YOU!!!