I think there is a whole load of rubbish which is being doled out from obscure textbooks. All the rubbish being written cannot prove that Aryans invaded India. Any one living in India or any sane person with commonsense would conclude would say this is utter crap. How would you then explain this recent archeological evidence - you can see this for yourself.
http://www.harappa.com/indus4/315.html

Aryanism is not a race - it is a way of life much like Hinduism is - although it is now identified by the set of people practising it. Would you argue that the swastika seal shown in the link must have been left by the nomadic wanderers who attacked this city?