Christening in a few weeks, help me find a dress.....please!

[monstersX2]

I am 5' 9", size 12-14, legs ok but belly needs a bit of holding in. Cant seem to find anything long enough (just above knee) and don't want it to be too dress nor too casual.
Actually on reading that back you can just tell me to push off

Oh by the way i'm a guest not family.

Coast have a dress called princess, i had it in blue for my sons christening, a fake wrap dress very flattering around the middle.

Thank You, lovely dress but bit to expensive for me, forgot to say my budget is probably £40 tops just to make it a bit harder! Also i'm not too good with colour, although i want to look nice i like to blend into the backround a little.
Another thing i forgot to say is i'm 25.