I have problems with my Xbox Online, I have Strict NAT but i'm not sure if thats complete fault for the problem.

When I set my online up I used Wireless but then i changed it to Wired, making it slightly better.

But my connection is still awful so i cant have a game without lag on Fight Night, i'm incappable of searching for a game on COD unless i join a friends session, takes me ages to get a game on FIFA, also out of around 80 Friends on Xbox i can only connect to a few of them.

Now I am just completely fed up of it,
So would it be better connection if I made a new profile (as now im creating it with a wired connection)?
Would it be better with the new 250 GB Xbox?
Is this the same with the PS3?
Is it to do with my provider talktalk?