Pricing

Is anyone out there familiar and could help me with some pricing. I was asked and hired at a flower shop to help with a wedding and Mother`s day flowers the 2 days before Mother`s Day. I was assisting their designer. After several hours of being there was an argument which resulted in the floral designer walking out. I ended up doing the wedding flowers by myself.
I have my own event planning business that I just started 2 months ago so this was just something to make some extra money.
It has turned out to be great but now I have a little situation. My status at the shop has changed from our origianal agreement. I have been working as a contracted laborer, really on call when they need me, meeting with the brides, mothers of the bride, meetings onsite at the reception or church location, conceptual design, floral &silk arranging etc. They do not have another designer.

My question is what would be a fair amount to charge them either for an hourly rate or percentage. I don`t know if anyone has done worked this way and could offer some advice. I live in Oklahoma.

Thanks!!!!