You will be spinning your wheels. A wireless connection to you neighbor will do very little to improve your band width. It won't provide rollover, coming from the same source. It's abvious you have not been on a wireless lan with 3 or more users.
But if you want to try. Your setup will be like this.
Your Cabel connection -> modem -> wan1of2
your game adapter to your Wan2of2.
Your neighbors cable to his modem -> his wrouter ->
Your neighbor lan must be on a seperate subnet than yours.