Upgrading to 1.1b2, not reading my old data

[allQoo.com]

I followed strictly your standard upgrade steps, including putting the settings.inc.php into the new config folder.

When the install script asked me if I were doing a new installation, or updating to latest stable version 1.0.0.8, I picked the former.

Then the script forced me to use database header other than the ps_, as it is already existing with content. I used ps123_.

What have I done wrong in the upgrading process? How do I get the shop script to read my data in ps_ tables?