My best advice right now besides the reading as sugested is keep doing water changes multiple times per day at this point as much as you can, watch for secondary infections that can come about from stress, see if you can get your hands on some fulter pads from an established and healthy aquarium (or gravel or decor...dont wash it and put it in...and if that fails, get a bottle of biospira to try and establish the nitrifying bacteria. I have read some really good things about that product specifically.
Water changes are your best friend in this situation. Every time you do it you will reduce the amount of Nitrite that is currently creating a toxic environment for your fish. You may have to keep it up for a while if you can't get that bacteria population bumped up, just make sure you are using prime or a dechlorinator every time you water change at the approriate level. If you are not sure how much water you removed over estimate it, you don't want to add chlorine problems and kill off the bacteria you already have going.
Hang in there, many of us discovered helpful communities like this because we didn't know about the full meaning of the cycle process and everything going on that is unseen.
