Crap! Ich break out, need AC's help!

OK so I've never delt with ich before. Read all about it, never delt with it. I am really not even sure how I contracted it. Could it have been the WC I did recently? I did about 25% and cleaned about 25% of the decor, added some sand and a few plants. Plants came from invert tanks. Anyway I am pretty sure the plants won't make it through the treatment. I found 2 platies last night COVERED in this crap. They didn't look like that yesterday before I left for work but when I got home I feaked. I broke out the QT tank, seperated the fish and am treating with high heat and salt. I also turned up the heat in the main tank and added salt. I am worried I have 2 cory cats in there and I know they are sensitive to salt. I also have 5 tetras, which I think are as well. My black molly looks like he has it this morning, his mate has disappeared and the male swordtail is banging off the rocks, his mate looks unaffected so far. I am sure it won't be long before they starts to show signs. :swear::swear::swear::swear:

Can someone please advise me on what to do here? I read the post Lupin has stickied on "white spot disease" and I think I am doing all that. I fear to treat with anything else because I know it can harm inverts and I have 2 amano shirmp and a bamboo shrimp in the same tank. :help:

OK so it sounds like I am on the right track I just have to be patient. I hate seeing my fish like this. I feel so aweful, like a bad parent or something. *sigh* Alright I will leave everyone in the tank and just stick to the salt & heat (I didn't want to use anything else cause of my inverts & the possibility of crap leaching out of the silicone etc).

What can I do about the "cold" spots in the tank, I am trying to keep the heat up around the 80's, but it seems like one end of the tank is only hitting about 75. Thanks guys!!

I have both, a powerhead and another heater. I actually just removed the power head before all this happened I guess I will be putting it back in.

UPDATE: both tanks starting to show signs of improvement. Lost 2 platy fish to stress (they were COVERED in this crap) but 2 black mollies in QT and 2 platies in QT looking better, eating, and seem to be responding to treatment. Main tank no other fish appear to be showing symptoms but I am continuing treatment. Will not be releasing others back into the main tank for at least 2 weeks after all signs are gone. Thanks for everyones help! I think the worst is behind us now.