SecurityAssist supports encrypted passwords with sha512. The latest version in DataBridge V2 supports hashing and salting in the libraries, but that would require some hand coding.
The thing that SecurityAssist wouldn't help with is going through and encrypting or hashing the existing records since they have already registered. To do that you would probably use the DataBridge update server behavior to loop through the entire database and update the passwords. This would require some hand coding and is dangerous since any mistakes might leave you with a database of users that can't log in. Make sure you back up your database before attempting this.
I'd start by encrypting or hashing a single user's record (yours) and create a separate login page to make sure you have all of the kinks worked out. Then build the page to encrypt everyone's record once everything works properly, making sure to back it up in case you make any mistakes.
Consider how necessary this really is. Do you store sensitive data in your database that you are worried about a hacker getting access to? The level of encryption should match the application and what data is being stored. If you have credit card numbers and social security numbers, then hashed passwords and encryption on those fields is necessary, but if you are just maintaining a member directory, then it might be overkill.