For future cream cheese icings, don't over work the butter and cream cheese. When you beat or whip cream cheese and butter it causes them to break down and release their water, making a soupy icing that needs a ton of powdered sugar.
Get the butter (or shortening) and the cream cheese to room temperature. Mix the fat, vanilla, salt and powdered sugar into a very very thick buttercream, beat until smooth. Add the softened cream cheese to this very stiff buttercream and mix on low until nicely incorporated, DO NOT WHIP. It will be nice and thick and spreadable, nicely sweet and the tangy flavor of the cream cheese won't be overwhelmed by the sugar. There is a recipe on my blog, just follow the link in my signature.