I agree with Monsoon! Laura Ashley is a bit of a gamble.... not always great. Are there no children shops (not big brand) where you live ? I found gorgeous christmas clothes for my kids in one of those (and they were 50% off too!)
If you are splashing out then try Kent & Carey (shops in SW LOndon), Tati (shop by main order/online). Can you sew? I made two VERY VERY simple skirts by simply sewing together two very long rectangles of silk with a fat piece of elastic through the top which looked fab. with a cream top/cardi/jersey and cream tights and polished shoes.
Oh forgot too. If you want party type dress, try BHS. They have a wedding range, which includes girl's dresses. Most are for Bridesmaids dresses, but some could easily be used as a wedding guest wear too. And very reasonable prices generally.