Well, that's because moreResultsUrl is pointing to http://www.google.com/search instead of http://ajax.googleapis.com/ajax/services/search/web.
What you need are just the parameters of the moreResultUrl which you can pass to http://ajax.googleapis.com/ajax/services/search/web for the JSON result.
For example:
http://www.google.com/search?v=1.0&q=Luca
is translated in JSON with
http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=Luca
Google is just showing you their RESTful api, it's up to you to use the pages JSON value with whatever interface you want.