Restoring data help

One of our boxes recently had a crash and the sys admins solution to get it
back up and going was to run a OS upgrade, the box is running RH 7.1 now.
The RH upgrade appears to have run a upgrade on the PGSQL database and now
the db will not start due to: "An old version of the database format was
found." From looking at the docs, it says to take the database to the
previous version via: "rpm -U --oldpackage" I will admit that I am not a
master of RPMs but my attempts at running this got me just errors:

[root@magicbox aaron]# rpm -U postgresql-7.0.2-21.i386.rpm
error: failed dependencies:
postgresql = 7.1.3 is needed by postgresql-server-7.1.3-2
[root@magicbox aaron]# rpm -U postgresql-server-7.0.2-21.i386.rpm
error: failed dependencies:
postgresql = 7.0.2 is needed by postgresql-server-7.0.2-21

Is there another way to go about changing the database to the new format
(PostgreSQL 7.1.3)?