ElGato Game capture works wonders for video capture. It is kinda expensive, depending on your budget, but worth it.
If you are on a tight budget, you can check on those cheap USB capture cards (EasyCap). They may not have a superior quality, but at least you can capture video and use it to stream.
Hope this helps (even though this was an old post, but no one responded)
Experience - I own an EasyCap and getting an ElGato soon.
EasyCap Vid - http://www.youtube.com/watch?v=peLdwr1ACr0
ElGato official page - https://www.elgato.com/en/gaming/gamecapture-hd