I'm afraid I don't have the ability to get wifi on my DS currently =< Sorry.
I can offer you the advice that they do appear in chargestone cave, though. You just have to be patient.
That and the advice that only Tynamo's second and pre-final evolution can learn moves through leveling. That means if you want it to learn really good moves such as Coil, or Thrash, you have to wait until like level 75 before evolving it to it's final form.