Found extremely lethargic barely responsive baby possum who can I call for help and what can I do?

He is about 9" from the tip of his nose to his rump and curled up in a fetal position at the bottom of my garbage can.He is barely responsive but will look up when I shake the can . He is not eating and I was not sure what to feed him so I gave him franks and beans and apple pie and left water in a bowl outside near the can in case he climbs out. I don't even know if he can climb out. I tried turning the can on its side but he still did not leave. He's just lying at the bottom of the trash can occionally looking at me I think. He seems like he is dazed all he does is open his eyes and then close them and go back to sleep.I first saw him at 11 a.m. today and there is no change in any of his actions since then. I put a blanket over him as he is so small and all alone and I thought he may be cold?He has changed his position once in awhile,about 3X since this morning.I don't know how long he's been there as I just returned after a one week absence and live in rockaway park ny and have no idea who if anyone I can call. I have no car and so cannot bring him anyplace nor do I have a clue where I could call for them to come get him. I fear he will be dead by morning and feel helpless. I think he is dying slowly why or how or from what.Iknow not from what but IT IS BREAKING MY HEART. HELP