php4 and postgresql 8.3

My basic question is...are php4 and postgresql 8.3 compatible?
I'm running Linux Redhat 3.4.6, php4.3.9, and postgresql 8.3.  I know,
some of those versions are old...its government, and I unfortunately
don't have control over the version.  In fact, I don't even have root
access right now.  But I've got projects waiting to go live if I can
get php and postgresql to talk to each other.
When I try to connect, I get...call to undefined function pg_connect.
When I look in the php.ini file, there is no pgsql.so file, and in the
extension library in /usr/lib/php4...I only see ldap.so.
So do I need to have the IT person download the pgsql-php rpm?  Will
that take care of this?  This might be the only option, so hoepfully
there's something I can do.
Or should I just push to install php5 if they let me?  Will php5 and
postgresql work together inherently?  Or will I need to add modules to
the initial php5 installation?
Thanks for any help!
Shad