McCannilbal, that's not a good response. If you think your deck will become super just by adding a Leader, think again.
Vanish, your deck consists of many low star cards. They are definately not bad, but some 4 or 5 level cards would do your deck good for some heavy damage! therefore my advice: get a Don as soon as possible, he is awesome.
Also, Ottavia is a must-have in every Montana deck!
Then, if you have any clintz left, try to get your hands on a Copper. He is a powerhouse as well, but you can live without him.
note: If you want to build an ELO deck, my advice is not to use Montana or Sentinel.
Then it would be something like this