How to programmally add nodes with next nid?
Try this way:

  $node = new stdClass();
  $node-&gt;title = $new_array['titre_csv'];
  $node-&gt;type = "livre";
  node_object_prepare($node); // Sets some defaults. Invokes hook_prepare() and hook_node_prepare().
  $node-&gt;language = LANGUAGE_NONE; // Or 'fr' in your case
  $node-&gt;uid = $user-&gt;uid; 
  $node-&gt;status = 1; //(1 or 0): published or not
  $node-&gt;promote = 0; //(1 or 0): promoted to front page
  $node-&gt;comment = 1; // 0 = comments disabled, 1 = read only, 2 = read/write
  $node = node_submit($node); // Prepare node for saving
  node_save($node);
  //save the other table


If you want to save it in your custom table you can do a db_insert or EntityFieldQuery.
In that case $node->nid value will be taken after you do the node_save (so do it after you save it with node_save).
You could also use a hook_schema for your table.