If you want to keep the stock wheels, it basically means that you're going to have to use a 235/55R19. I only see one tire marketed as off-road in that size available in the US, and it's fairly expensive compared to other options. There are a few options marketed as highway all-season that will be somewhat more aggressive than the stock Toyo tires, but I have no idea what you can get in Colombia.
Of course this is all based on the assumption that your Signature uses the same wheel size as ours does...