The problem with acne is that some products that help heal acne, is also very drying on the skin. So if you already have dry skin that can be a problem.
I'm sure you have met with a dermatologist regarding your acne. Follow his/her instructions.
Using a good moisturizer is important. Neutrogena carries very good lines of moisturizers and cleansers for dry skin. They usually don't have a lot of chemicals like some brands. The new Neutrogena Naturals are excellent products for dry skin
As for makeup, I'm a big fan of Bare Minerals foundation makeup. It is a dry powder makeup that is applied with a brush applying it one thin layer at a time. But with having dry skin, you would need to make sure your face is moisturized before applying the makeup.
Revlon Color Stay liquid foundation for dry skin is good. It gives good coverage and doesn't rub off. It is best to apply liquid foundations on with a small cosmetic sponge.
To find your right makeup color, dab a bit of foundation on your jawline and look in a mirror with natural light (stand by a window when the sunshine is shining in). If you can see the color, it isn't the right color for you.