Anyone fancy a challenge?
I'm looking for an outfit for my son's christening in April and I'm completely lost and don't know where to start (figured it's either I've never worn anything that actually fits me or my body has changed so much post-pregnancy, it's like I'm getting to know me again 
). I wouldn't want to spend too much on the outfit, as it's only a small do, but would like to look smart nevertheless (and ideally be able to wear the outfit / pieces again). Probably max £50 - £100 if it's top. skirt etc. I hardly ever wear dresses so would like to look nice for once!
It would need to cover my knees and shoulders (can be dress and jacket if dress is sleeveless) - lighter colours preferred, so ideally not black or red (I'm thinking even dark purple would be too close to what the priest is rocking this time of the year). I'm paleish with medium brown hair and hazel eyes (if that matters!). I'm petite, somewhere between hourglass and rectangle with longer torso a bit of a mummy tummy I'd like to hide. Also, the outfit would need to go with flattish shoes (foot problem, my name explains why...
). Demanding, much? 
Anyone with more sense / fashion sense be able to point me in the right direction please? What sort of things should I be looking at / best places to search for a suitable outfit?
Thank you very much!