no, you will hopefully have the beginnings of some bacteria in your filter now. any tap water will have mixed in with the tank now. now just leave the filter for at least a month, unless its starts getting clogged up and you notice the water flow drops, but it shouldnt do. you really really need to get a lot of water changed though. the longer you leave it the more likely more fish will die. sorry to sound harsh, but thats the way it is. because the tap water has killed your bacteria, your fish are living in their own poo, which as you can imagine is not good for them.
as an example, i lightly squeeze my filter sponges once every couple of months in old tank water. i cannot stress enough how bad un-dechlorinated tap water is for you filter bacteria as well as your fish.
you are now in what is called a 'fish-in cycle'. you are trying to build up your bacteria while having fish living in the tank. this is not ideal as until the bacteria get to the correct level, your water is poison to your fish. this means either re-homing the fish somewhere, getting a filter or sponges that has already been used and is full of bacteria, or more likely changing lots of water out EVERY DAY until the bacteria is set-up. check out this link for more info
fish in cycling
with the ammonia levels you have and the lack of bacteria, i'd say 50% is the minimum you need to change. changing water will cause no harm to your fish , as long as its dechlorinated and roughly the same temperature. use tap water, but put the right amount of dechlorinator/tapsafe in it.
1. leave filter as it is
2. get some dechlorinator/tapsafe
3. change at least 50% each day and keep testing to see what affect it has. up the amount if need be
4. read about fish in cycling from the link i gave you
5. dont slack with the water changes until your filter has recovered.