What to wear at a summer wedding?

I'm going to the wedding of a good friend of mine this weekend (gosh, she's a couple years younger than me - and here I am gotta do a post on my utter crap taste in men). Anyway, this wedding is going to be pretty hippy - the bride, groom and most guests are camping on the night of the wedding. I've got myself a hotel room. I can just about manage festival tents - but to get ready for a party?? Nope.

I need help. I've looked at so many dresses, searching for something unique, that in the end all the dresses blurred into one. All the dresses around at the moment are pretty short in my opinion and don't know how suitable they can be to a wedding. I ended up in a high street shop - Warehouse - and picked up a salmon coloured dress that seems to be a hybrid between a ra-ra skirt and prom dress. At least I know I will be the only person in this dress, most people will be far too trendy and 'cool' to be wearing mass produced clothing. It was on sale for £40. I'm not over ecstatic about it:

Trust me, they look better on

I'm thinking gold jewellery, with specks of pearl. The couple's request is for all guests to wear a head piece. I have absolutely no clue what colour or thing would suit this outfit. Any good recommendations for a good place to buy a cheap fascinator? The dress comes up a couple of inches above my knees, and coupled with a pair of sandals a bit similar to this, I'm a bit worried it might be a bit inappropriate especially as it will be a church ceremony. The main thing that makes me still want to wear it is that the corset bit helps flatten my lower stomach is currently resembling a mini hill. But I don't want to feel uncomfortable around the couple's parents and family. Does anyone think it looks a bit tarty? Should I go for a different type of Sandals, or different dress altogether.

The hen do was much simpler to choose. This is from the Top Shop boutique:

On sale for £20

The weather in London is almost unbearably hot. I have tanned so much that I feel like I am unrecognisable when I see myself in the mirror. I really hope it cools down by the weekend in time for the wedding.