Give it some more time. It has only been a week. Leave the beer on the original yeast for another week or two and check the gravity then.
I never had any luck getting my extract brews past .020.
I don't understand this. I have done a ton of extract or partial mash beers and never had a problem getting them to finish where they are supposed to. I have had extract brews finish as low as 1.003. Of course that was a Saison using 3711.