The judgment creditor can garnish your bank account. In order to do this they have to file a lawsuit against your bank. Once the bank has been served with the lawsuit the bank will freeze your accounts. Any and all money in the account will be turned over to the judgment creditor after the bank takes out its legal fees, usually around $400-$500.
Yes they can take every penny in the account (up to the amount of the judgment). They can do this as many times as they want to until the debt is paid.
Now, in order for the judgment creditor to do this, they have to know where you bank. If they do not know where you bank, then they do not know what bank to file the lawsuit against. So if you think they know where you bank, change banks and they wont be able to garnish the account.
There is no good way for the judgment creditor to find out where you bank unless you tell them.