Let me get this from the top. For the file I posted, you need the node_import module, you can get it from http://drupal.org/project/node_import

when you extract it in your modules folder, go to
/modules/node_import/supported/ and create a dir ubercart in it, place the .inc file in that dir, you get
modules/node_import/supported/ubercart/uc_product.inc

the node_import module includes all stuff under the supported dir, so no other actions should be required.

If you want to import images, have a look at http://drupal.org/node/143471
unfortunately, that solution is not yet generic, so you might have to do some manual adjustments (like the name of the image field you want to import to)