This is from another site but maybe it will help you. Someone there asked the same question. Here is the reply.

He needs food right away if he hasn't been able to get to any nectar. Can you get your hands on a feeder or a shallow bowl to put sugar water in (1 part sugar dissolved in 3 parts water) You could probably start with I level tablespoon or teaspoon of sugar in 3 tablespoons or 3 tsp of water depending on what you may be able to find there at work

One of our members is a rehabber Here is her information. She is in Virginia but she can help you over the phone
Connie & Wilton Sale
757-482-4796
State and Federal Permits
WildLife Response, Inc.
NWRA, IWRC
Hummingbirds and Small Passerines
humnchirp@verizon.net
http://www.wildliferesponse.org/

I'm assuming you were able to reach the recommended rehabber, but in case not, the link below contains a link to help find wildlife rehabbers (not necessarily for hummingbirds)

Here is a link that might be useful: Emergency Care for Birds

How did everything go with your hurt hummer? Did you get help? With all these hurricanes, I'm just hoping our babies made it South OK.

Sorry it took so long to come back on and let you know.

I kept the little hummer till I got off of work on Friday. (2:00 pm)I then took her over to Willowbrook Wildlife Center, in Glen Ellyn, Il.

I am hoping all went well and filled out a form for them to send me a post card with the results. No phone info.

I fed her every half an hour till 12:30 am. then resumed her feeding at 6:00 am. A very nice lady named Jean called me from California about midnight and talked with me till about 1 A.M. She is known as the hummingbird lady out there. Jean was able to help me a lot and gave me great care information. She has been doing Hummingbird Rescue for 20's I believe is what she said.

I feel very privileged to have had the chance to take care of such a wonderful little bird, but feel bad that it was because it was hurt.

Thank you to all who took time to answer my question.

Katie