Try MoCA, but if the coax run to the TV is part of the cable network, read the following thread. You don’t want to be sharing a network with the neighbors by accident. (Mostly a theoretical possibility, but still.)

http://www.snbforums.com/threads/moca-security-concerns.14490/

If MoCA doesn’t work out, you can always play with wifi extenders. They basically act as repeaters/amplifiers, and might get wifi to the TV.