Extract NGUI Tweening from NGUI package

I require some help with NGUI tweening. I am using Unity UI system in some of my games but I want to use the NGUI Tweening system in those games and don't know how could I extract the NGUI tweening system and import that in my game. I don't want other NGUI components to be added in my project because it takes extra space and I can't afford much space as I am developing mobile games.

Sorry for the bad English but please help me out with that, I am really stuck here.

Regards