Triumph of the Hordes is a scary, scary card.  1/1 elves aren't supposed to be able to infect you to death, especially not in one turn.

what you want to do is get out elves very quickly. Tribalforcemage is the man. Along with imperious perfect you can make a crazy amount of elves. Another nice touch is triumph of the hordes,trample and infect,with a bunch of elves attacking you all at once. (Ouch!) heedless one helps as well built in trample is great. this deck is pretty quick but sometimes it would be smart to take a small amount of damage and then swing in with forcemage or hordes or both at the same time if you have archdruid out.