The head is Mini USB. That connector is used for PDA's and smartphones... I don't know why they need it for the keyboard, maybe PDA's use keyboards now, I don't know. Anyway, finding the connector will be very difficult, I am sure not immpossible, but not easy. If you can, I recommend returning it for a different one...
Just found something here:
Universal Serial Bus - Wikipedia, the free encyclopedia
Read up, even shows the picture.
BMH
Maybe that'll help