How to connect to an remote PostgreSQL database on Ubuntu using pgAdmin3?
The line in your netstat report shows that the database is only listening on localhost:5432 (127.0.0.1) for incoming tcp connections.

Proto Recv-Q Send-Q Local Address   Foreign Address  State   PID/Program name
tcp        0      0 127.0.0.1:5432  0.0.0.0:*        LISTEN  3561/postgres


So it can only accept local tcp connections regardless of what permissions you've specified in pg_hba.conf. pg_hba.conf only specifies allowed connections, but does not specify what interfaces your service will listen to.

The addresses the server listens on is specified with the listen_addresses GUC in postgresql.conf.  If you want the server to listen for remote connections you should specify the ip(s) you want it to listen on or * to listen on all available interfaces on the host.

To have your postgresql server listen on all interfaces on the host, you should have the following line in postgresql.conf:

listen_addresses = '*'