Is your product for restaurant/cafe/bar owners or customers?
If you want to show your idea to restaurant/cafe/bar owners, why do you need a screencast? Just go and talk to them.
It sounds to me like it's too early to talk to bloggers.
If you have a budget, there are a few people who make pro screencasts for companies. If you search HN you will find some recommendations.
But I would suggest just make a screencast yourself first. It will help you think through what you want to show and get the script right, which you will need anyway even if you get someone else to make it for you.
Finally, if you have something to show just put it up already and ask people for feedback on the real thing. I know it must be embarrassing if you don't have the most amazing solution yet, but you have to start somewhere.