This could be $10, or $50 question.
- Visit your local Walmart / BestBuy / etc, and look what "universal remote controls" they offer, then check whether they support your TV. If not - see whether any of
Logitech universal remotes work for you.
Last but not least - dig out and find the user manual for your TV, and see whether there are any buttons to change channels or inputs. And make sure you know what this "game channel" is (I suppose this is an input where you've connected your game console).