I'm no expert, but I got through this just the other day.
It is a PostgreSQL database running on the client. You need to basically "unlock" the database for access from other machines, but it is 100% possible. Here is the rough outline.
1. Reset the root password to something you know by starting the VM in single-user mode. Google this.
2. Log in as root. Then reset the postrgres user's password to something.
3. Log in as the postgres user. Find the Postgres configuration files to enable access from outside this VM. You must have the postgres user to do this, hence steps #1 and #2. You can Google "connect to Postgres from different machine" for the details on the files and how to edit them. This is standard Postgres stuff from what I can tell.
(By the way, you can always just ssh to the VM with the admin/admin user/password.)
Once that's been done you should bounce the server, or at least the postgres database processes. Then you will be able to connect from any other machine or Postgres client.
You still need to find the password though. There is a file within the application folder with that configuration. I don't recall the name or path but it was very easy to find once I found the java process.
Try running ps -eaf | grep java and look for the java process with the long command. In there you will find a couple interesting folders where the application itself lives, and in one of them you'll find a small XML file that has the postgres user, password, and DB name.
All said this took about 20 minutes of Googling and digging around the VM to figure out so it wasn't too bad.
Wow awesome knowledge I'll be trying this out when I get back from holidays ill post back here how I get on have an awesome xmas