You are doing perfect :)
Extend the article class with the attributes, that you need. They will appear in the admin site automatically, because the admin site uses no template and thus, ez just prints all attributes.
For the user site, you need to insert your new attributes in the templates for your article class.
go for Templates /node/view/full -> article and /node/view/line -> article and have a look at "attribute_view_gui". Hope, this helps.