If you are looking for replacement magnets, go to Ebay and do a search for "Rare Earth" magnets or Neodymium magnets. These are incredibly strong magnets (I am not kidding, I've gotten blood blisters on my fingers from my fingers being pinched by two attracting magnets.)

You can find these magnets in varying sizes and shapes. They are also great for using in custom projects. Such as the Magnetic Feet Custom