Recover the ID and then the password by:
Is there a way to find my Apple ID Name if I can't remember it?
Yes. Visit My Apple ID and click Find your Apple ID. See Finding your Apple ID if you'd like more information.
How do I change or recover a forgotten Apple ID Password?
If you've forgotten your Apple ID Password or want to change it, go to My Apple ID and follow the instructions. See Changing your Apple ID password if you'd like more information.
Last, contact iTunes by:
Apple - Support - iTunes - Contact Us
or make an appointment at the Genius Bar of an Apple store. Bring your proof of purchase
Apple Retail Store - Genius Bar