problem after upgrade db missing

Hi !

I am long time user of postgresql (on several platforms), and last month
I came across weird problem...

I started upgrade of Ubuntu and halfway through, upgrade failed... I was
forced to do clean install. After install all my databases were missing
(I also had to reinstall postgres, so I installed same version of pgsql
I had before - 8.4).

Like I said before all databases were missing... One of thoose database
was very important, but since I didn't have time I didn't pursue it
further. Now that I can breathe again, I am here again... I looked
through data directory and I found in /var/lib/postgresql/8.4/main/base
I found 3 directories which leads me to beleive, that old databases were
not in fact deleted, they are just not "registered". Two of this
directories have old date (like date when my computer run on previous
version of OS) and one has new date.

Now I am not sure two of this directories are old databases, but I think
they are... Is there a way to register one of this databases into new
installation (I am sure that directory "1" is old postgres database, and
"11563" is my database I want to save, and "11564" is new postgresql
database (this is only directory with new date).

Any help is appreciated? I would really need data from that database...

Thanks for all help in advance.
Andy