Ok, I have been very hard on you since your first post...But you need to get your tank under control before you proceed with anything.
You have admitted that the tank is too small for your fish, this is a start.
You have ammonia, this is horrible and needs to be fixed. Several water changes will be in order. Possibly you can nurse the Porky back to help and find a home for him. Quit overfeeding your fish! You really shouldn't be worried about upgrading or new fish for your tank until your current tank has shown stability for a few months.
I don't understand how you are discussing buying new tanks and fish when you claim to have spent your last $ on a $30 fish.