Flush radiator

Have a drive thru oil changer or shop handle this and you can check repair prices here www.repairpal.com/estimator and find a repair shop here www.repairpal.com/directory

A reputable mechanic can test the radiator fluid to see if you have a cracked engine head or a leaking Head gasget. Probably Oil in your Antifreeze causing it to be black. Sorry but it sounds like you have some major repairs that need to be done ASAP.