upgrading, but learned about pg_dumpall too late

Hello,

I hope someone can tell me how to recover my database tables.  I recently
upgraded to a new Linux server.  First I saved a copy of my
/var/lib/pgsql/data/*, which was created with PG version 7.4.  On the new Linux
server I have PG version 8.1.11.

But now, trying use my old tables, I discover that I should have saved the
tables with the pg_dumpall command before I abandoned the version-7.4 Postgres
server.  Unfortunately I did not know about pg_dumpall.

So now I'm wondering if there is a way I can read and update my version-7.4 data
directory with my version-8.1 postmaster.

Here is one thing I've tried:
  bash-3.2$ pg_ctl start -D /var/lib/pgsql/old/data
  FATAL:  database files are incompatible with server
  DETAIL:  The data directory was initialized by PostgreSQL version 7.4, which
is not compatible with this version 8.1.1

Any suggestions will be appreciated.

Thank you,
Rich Hammer
Hillsborough, N.C.