If you have a look through the appropriate forums, you can usually find posts on things like this that contain your answers.
Just in case, I've attached a link to one of the many, many posts on what food to feed.
http://www.chins-n-hedgies.com/forums/showthread.php?t=2936
When you change foods, you should spend 4 weeks phasing in one food and out the other by feeding her:
- 3/4 old food, 1/4 new food for the first week
- 1/2 old food, 1/2 new food for the second week
- 1/4 old food, 3/4 new food for the third week
- All new food for the fourth week
So if you're running out of your old food you should buy it again, as well as the new food. Hedgehogs aren't like dogs, you have to be very careful changing their foods as their digestive tract can't handle sudden changes and they can get sick.