I think that the problem with the clique it happens everywhere. However, if your giving negative vibes it may be frightening them off. You know what its like when you are happy with a bunch of people you dont ask anyone else in do you?
I remember going to my sons nursery every morning for 3 years and hardly any of them lifted their heads up to say "Good Morning" then all of a sudden I broke the ice, I forced myself in - started talking, making an interest in their children, going on trips etc and now I have quite a few friends.
Why dont you make the play dates with the mums? If your feeling confident hold a charity coffee morning - that'll bring them in.
My son is starting church school in september and am I not letting anyone be-little me. I had it for 3 years and not anymore.
When I was in school I was never popular either, I never belonged in anyones group...I think its sad as I never had that friendship that others have which leads to life long friendships. But then I didnt make enough effort, I wanted to be a little unique. I see my parents werent a great help either.
Get your children joining groups, there must be lovely sunday schools, gymnastics, blar blar.