What's it going to take for TNA ratings to improve?
I live in San Antonio and I'd say most people I know have no idea TNA exists.
You basically answered your own question. TNA's ratings won't improve until more people know and care about TNA.
I think it's an uphill climb because pro wrestling isn't as big as it used to be. That means the pool of interested fans is smaller. All TNA can do is continue to produce solid shows on a consistent basis. They'll have to build their audience over time. It's not going to happen overnight.