How much would you charge??

I currently work in a creche at a gym.
The owner of the gym wants me to look after her daughter (who i usually look after in the creche as well) on the biggest horse racing day in warrnambool.
Im not going this year (saving my $$ for QLD) so i said i would look after her daughter and thats not a problem at all.
She wants to know how much i want an hour for looking after her...

So i have to take into account it will be from 11:30 till roughly 5:30, i will be looking after her at my house and it is a public holiday for people in warrnambool.
At the creche i get paid just over $17 an hour.

So what would you suggest is a reasonable rate?

Our babysitter who is a qualified childcare worker charges $10 per hour for private work. I would be tempted though on cup day to probably charge a flat $100, as what are the chances they would be back by 5:30?

She is pregnant so i cant see her being much later than 5:30.
Yeah i was thinking around the $100, only as it is cup day. Otherwise it wouldnt really bother me.
Thanks Astrid :)

I might be a bit out of touch, but I would've said $20 per hour. That's what any of the babysitters I've spoken to have quoted me... Mind you, I do find it a bit steep, but from what I can tell it's the going rate. HTH