First, please note my corrections to your post above, marked in red. If you're going to be teaching English to anyone, you need to be very sure that your own English (both spoken and written) is up to scratch.
Have a look at English Banana - it has loads of activities. However, be aware that the school where you have the interview might want you to come up with the activity yourself, rather than taking one off the internet.
Do you have any ideas at all?