Is there a reason that she has to be potty trained at day care right now? If not, maybe it wouldn't be a bad idea just to let her wear diapers or pull ups while she's at day care until she gets more comfortable with telling the workers that she needs to go. (And depending on how many other kids they are watching, and how attentive they are, the workers might not be picking up on your daughter's need to go - so it might not be all your daughter's fault that she's having accidents.)
If you just keep doing what you're doing at home, I would think that her confidence will continue to grow. But I just don't think you're going to be able to teach her to tell the day care workers at this point - because I think this is something the day care workers need to encourage/facilitate before your daughter would be able to really grasp it.
Congrats on getting so far in the potty training efforts, though! You guys are doing GREAT!