How much to feed a pregnant cat?
NO don't feed her milk. Argh.
Many adult cats are lactose-intolerant, and have problems digesting it.
When feeding the pregnant cat, people tend to overfeed early in pregnancy and not feed enough when the cat is nursing. For the first month of her pregnancy, feed her a normal amount of food. During the last 4 to 6 weeks of pregnancy, your cat's weight should gradually increase by 40 to 50 percent. For this reason, during the last 4 to 6 weeks of pregnancy, your cat should be gradually fed more and more food until she is eating about 50 percent more food by the time she delivers.
Also, I would highly recommend spaying your cat. There are already between 4 and 6 million kittens and cats killed every year in animal shelters because there aren't enough homes for them and people breed irresponsibly. They can even spay her during the pregnancy if you wish.
I think everything has been covered. :)