When you say you are "filing" bankruptcy. Does that mean that you have actually FILED, that is paid the fee, and submited the filing to the courts? Because until you file you have no protections under the Bankruptcy laws. But once you do actually file then automatic stays are put into place and creditors are not allowed to take any action against you to collect on any debts.
If you had actually filed and they attached your bank account after that, the Bankruptcy courts should require them to return that money, and the bank should(although not sure if fees are included) be required to return that fee. If they attached the account BEFORE you filed then unfortunatly they may be allowed to keep the money they had already taken.
Now, the one other thing to look at is the suit. They can not attach your account without having a judgment against you. If you were never notified(served) with the original lawsuit, you may have grounds to have the judgment vacated. In which case you would again be able to have the money returned to you.
This is something you need to go over with your lawyer, as they can give you the best course of action.
As for the $100 fee. Unfortunatly that is standard with just about any bank.