Cannot access Itunes with my new password

Make sure that you type the password in exactly as you did when you created it. That is, with capitals and lowercase exactly as it you did before.

If you still can't get in, try this Apple article: If you’ve forgotten your Apple Account password – Apple Support (UK)

You can also use the Forgot Apple ID or password? option that is on the sign in screen:

I assume therefore, that you have created a second Apple ID in order to start this discussion. If not, then you've got into your account here with that password, so it should be simple to get into iTunes as well.