You are not pumping enough. You should be pumping both breasts at the same time for about 20 minutes every two to three hours. Doing this your supply will increase. Artificial milk will never give her the nutrition she needs.
Check out kellymom.com for ways to get her back to bf fulltime.
Partner to an awesome man.
Mom to two boys (12 and 6) and a little girl that came when she was supposed to despite our plans (June 2013)
Stepmom to two girls, 21 and 5.