Our wifi is part of the cable modem
As long as your TV has a free HDMI port, you should be fine.
As others have said, there are multiple ways to access netflix. When you sign up, you can watch stuff on your comp, tablet, or you can watch it on your TV
If you don't have a smart TV then there are numerous products that would help you out
Amazon Firestick
Apple TV
Roku
etc
The roku and Amazon options are like.. 30 bucks. And will allow you to access not just netflix but things like hulu, hbogo, etc