OK - You have reached your ammonia spike and the beginning of your nitrIte spike by the sounds of it. Both these substances are very toxic to fish. You need to continue doing daily water changes until you ammonia is at zero. You must then keep a close eye on the nitrIte so that it does not spike too high, and do appropriate water changes if it does.
Definately do not add anymore fish until both ammonia and nitrite are at zero, and when the time comes be careful to only add a few fish at a time because you will most probably spike again during the cycling period.
I think while the ammonia is that high that you should do at least 25% water change if not 50% perhaps someone else could confirm that as I not too sure on quantities (my lfs guy guided me through the amount to change)
Hope this helps
EDIT sorry your last post was while I was typing. 20 fish in one go is far too many. You will really need to keep up with your water changes. Someone else more experienced than me will offer you more detailed advice I'm sure. You may spike really really high with that sudden load.
EDIT (2) I hate lfs's that are willing to sell so many fish in one go
Cycling will eventually fix it, but its a way off yet before your tank is matured. Right now the only way to reduce your toxic levels, is constant water changes. I know it seems like a lot of work, but it's the best thing for the fish.
May I suggest you also read up some more on cycling tanks, it may help. here's a start New Tank Syndrome
There is stuff that some people buy, but from what I've read I would not use it, and a lot of people on TFF do not seem to agree with it either. (though i'm sure your lfs would recommend it - anything for a profit) (sorry i'm so cross they have sold you 20 fish in one go, in a new tank )