Do you have a gas line already plumbed to the fireplace? If so, you just need some gas logs for the conversion. Otherwise, get some quotes from local plumbers for running the gas line, that's the most difficult part. Installing gas logs is very easy and the plumber can do that after the gas line is run. If you want to see the most realistic gas logs, check these ones out: Grand Canyon Lava Series Gas Logs.

I can help you with a Custom Fireplace Screen to replace those old glass doors so it looks more like your inspiration photo.

What plans do you have for the hearth and the stone around the fireplace?