Adding nodes to top navigation bar using object model

Question

hi,

  i have to create a node to topnavigationbar. each node will have some pages 

 node--
        page1
        page2
                 
1) i am able to create the node and adding pages but on the top navigation bar  when i click the node  the list is not collapsing ...

2) for pages i add i need to pass url
 the url i an passilng is
  "/pages/pageviewer.aspx?RC=" +rc+"&RD="+rd;
but when i am check in the navigation under site settings --

the url it is taking is  "/pages/pageviewer.aspx"

can any one provide links or solution