My baby girl is 3 months old. How much formula should she be consuming & how much sleep should she be getting in a 24 hr period?

Depends. Your baby's weight and frequency of feeding as well as the weight percentile on the growth curve determine how much he/she should eat. A premature infant may have a more rapid rate of growth, and consequently a proportionally higher volume. Average babes should eat every 3-4 hrs, and be allowed to stop when they are full-not necessarily when bottle is empty. Sleep goal-about 13-16 hrs/day.
Varies some. Most infants in this age group take in about 24-26 oz formula/day and sleep 14-16 total hours/24.