what is the correct consistency for cream cheese frosting I'm having an issue making decent cream cheese frosting.

I have a recipe that says to use:


  1 pound (450g) cream cheese, at room temperature
  4 oz (110g) unsalted butter, at room temperature
  2-3 cups (240-360g) powdered sugar, sifted
  a few drops of vanilla extract


and then to


  To make the frosting, beat the cream cheese and butter together until smooth. Slowly add the powdered sugar (do this on low speed to avoid a dust cloud) and mix until light and silky. Add the vanilla.`


The problem I have is that it comes out way too runny to frost anything with.  I've tried adding a bit more powdered sugar and it still maintained it's runny state.  I'm using the K paddle for my Kenwood mixer to mix the frosting.

I've put the icing in the fridge for the moment to see if it will harden up a little.  Is this standard or am I doing something wrong?

EDIT:

So after putting the cream cheese in the fridge for a few hours, it still didn't harden up, just turned a cold runny goo.

One thing I have noticed is that the supermarkets in the UK sell "Soft Cheese" as opposed to "Cream Cheese" which makes me think there is a difference between cream cheese and soft cheese.  Philadelphia in the UK is sold as Soft Cheese, and many UK based recipes that include a cream cheese frosting often include lemon juice.
My current favorite cream cheese frosting recipe comes from Thomas Keller's book Under Pressure - page 218. The proportions of the major ingredients include:

cream cheese: 100%, butter: 68%, sugar: 132%

Your recipe uses:

cream cheese: 100%, butter: 24%, sugar: 80% (using the maximum recommended amount).

It may be that you just need a lot more sugar (or more sugar and butter), or it may be that the cheese being sold in your part of the world is not the "cream cheese" we know of here in the USA.