To follow up on Kriston's (and others') suggestion... Google "homeschool" and "montessori" and then join a few montessori homeschool yahoo groups. seeing what other parents are doing may boost your confidence.
As you may suspect, your daughter might be resisting change right now because she just went through a huge transition leaving her Montessori environment.
What kinds of afterschooling activities are you offering? Maybe if they look like what she is used to from Mont. she would be more interested...
Good luck!
EW