Computer Problem - Nvidia 9800GT Issue

PROOF OF 9800GT! Links for this topic: Power Supply im thinking of getting - I need your help with my problem the specs are in the video so theres no point putting it here. And basically my 9800GT doesnt work properly its laggy and the graphics arent as good as there suppost to be. Now this card is the green edition so it doesnt have a slot for a 6 pin connector. Also I have no idea if my powersupply is powerful enough because it doesnt say the amount of watts at the back of it.