Crank the heat up to 88 degrees F (for a couple weeks) and dose whatever medication if you'd like. Also, there's a method that involves filling a bucket or hospital tank with water, adding aquarium salt (forget the amount I think it's 1 tablespoon per gallon but don't quote me on that) and one by one giving your infected fish a salt bath in that solution. You can literally see the Ich back out of the host body.
As for the increased heat, that speeds up the life cycle of Ich and promotes the infection to leave the host body much faster (within a couple days). The reason you should leave the heat so high for a couple weeks is to insure that the Ich don't reproduce once they exit the host as they don't have the ability to do so in such high temperatures.
Good luck, hope this helps.