Lynn, I'm so glad that you got Katie back!

As far as the baby goes...
The back of the formula container will tell you how much to feed per oz of kitten. Weigh the kitten to figure out how much its total daily volume is, and divide that by the number of feedings you are doing each day to find the volume the kitten needs to get per feeding. I always try to get at least that amount in, if not more.
In doing the math, it is easier for me to convert everything to mls and grams. There are 30mls (or grams) to one oz. You want the kitten to average around 120g weight gain per week, or one lb/month.

Eyes open means around two-three weeks; I usually bottle them until 5-6 weeks old. I provide water and a litterbox (a very shallow pan, or disposable baking dish) at 3 weeks, and soft food/weaning formula at 5 weeks. I've had a few transition to solid food at 4 weeks, but most seem to take longer. KMR is my preferred formula, and I recommend buying a canister of the powder for around $25, as it will go much further than the little cartons of pre-mixed. They also make a second-stage weaning formula that works very well, especially in combination with the little jars of meat-based baby food.

Also, if you post a close-up picture of the genitals, I can sex it for you.