The whole oily foods gve you acne is a myth. Everything in your food is digested through your stomach, its natrual hormones that control how your skin acts/reacts to certian things, although drinking water will help pass impurities out of your system, which will spurr up the hormones that cause it. I've got horrible acne, but these things tend to help some, to keep it managable:
1. Drink lots of water, as I said, helps impurities pass through your system faster.
2. Don't lean your face on your hand when sitting down. Your hands produce oil, and that direct contact will pass oil from your hands to your face, and thus into your pores.
3. Wash your face with cleansers, not soaps. Soaps will dry out your skin, and your face will want to replenish dry skin by producing more oil.
4. Clearasil or whatever brand Oxengenating pads seem to help, as they open pores to oxygen.
5. If your problem is bad, look into medication. Go to a dermatologist and request Acutane. There's also a brand called Natural Lindy that produces some great stuff out in L.A. You can order it on their site, but its kinda pricey.
Thats about all the help I can offer. Good luck.