Normally the best thing to do is put the nest back somewhere high and hope mom comes back but if they were so cold already maybe she was already gone and if it's dark she is probably settled down somewhere and they wont make it through the night. You could try putting them out in the morning if they make it.

They need liquid most. You can pry the mouth open gently and put some in a drop at a time. All food should be mixed with water but they must be warm and hydrated before giving them food. You will kill them by putting food into a cold bird.

Then the best food for song birds is dog food watered down.

See here
http://www.starlingtalk.com/babycare.htm
http://www.starlingtalk.com/dogfood.htm
About starlings but true of most all native song birds