I need SEO help, with or without plugin

Hi,

I have a big big big problem with my WordPress. And I really don’t know where to start. On Google webmaster tools it says I have 546 Pages with duplicate title tags out of 160 posts in total. I’m not sure exactly how did I cause this, I just know 3 things that might affect it and then brake everything:

1. I have used 2 different plugging for automatic translation of my website, one of them, that is the one I use still now creates a URL like this http://www.app42day.com/en/angry-birds and the other one that I disabled and uninstall use to do it this way http://www.app42day.com/angry-birds/?lang=fr

2. My blog use to be in another server and the URL’s used to be like this http://www.app42day.com/apple/angry-birds/ and now they are simply http://www.app42day.com/angry-birds

2. I have changed the way that my WordPress creates the URL’s, before it was http://www.app42day.com/angry-birds/ and now is http://www.app42day.com/angry-birds

As a result of all of that my actual webmaster tools shows for loads of different posts different URL’s such as (please this are just examples, it might not be with this actual URL but it is all kind of repeated content it shows on Webmaster tools):

/angry_birds/
/angry_birds
/apple/angry_birds/
/angry-birds/?lag=fr
/fr/angry-birds

and it does the same with pages:

/2011/03/
/2011/03/page/2

Please please please need some help I really don’t know what to do and where to start but this is affecting big time my statistics in Google and Alexa Ranking. It looks like it is picking it up as different pages with duplicate content and it is not, if you put any of the variations in the browser they all redirect to same place, the correct post.

Thanks a lot
Kind Regards