Installed postgres.app 9.3.1.0. pgadmin doesn't appear to see it

I uninstalled 9.2 before installing 9.3.1.0.

The app is called Postgres93, it is version 9.3.1.0
I downloaded the latest pgAdmin, it is pgAdmin3 version 1.18.1

I have a database "MiniServer" which is supposed to use postgres
as its Maintenance database.
But there is no such database.

Perhaps it can't find the DBs that were there?

pg_upgrade requires

pg_upgrade -b oldbindir -B newbindir -d olddatadir -D newdatadir [option...]

but I'm not sure what the 'old' values should be (since I uninstalled 9.2 -
maybe I shouldn't have?)

In my /Library/PostgreSQL/9.2/data/global I see 42 files fom 8K to 25K in
size, most created
last March - my data must be there. So that may be telling me to create an
empty folder,
/Library/PostgreSQL/9.3/

In my Postgres93 bundle there's a Contents/MacOS/postgres, a small unix
executable.
Is that the binary? But again there's no binary for 9.2.

I was rolling along with 9.2 getting lots of good work done via
Eclipse/JDBC.
But now I'm stuck.

Sorry for being so dense. But I've never been afraid to ask questions.
The answers I get increase my understanding of whatever the topic is.

Thanks in advance for helping a tyro.

- Bob