Command and Conquer Generals Zero Hour

I can't get online with Generals Zero Hour but heard I could use some other program besides origins to play online. Does that mean I'd have to re-buy the game? I've already bought several copies of The first decade then a copy of The Ultimate Addition(Origins) and I really don't want to have to buy it again just to play online. I've been playing for years and can beat 7 Hard AIs. I want to play online for more of a challenge! AI's are just tedious because they do the same strategy repeatedly. Not complaining AIs can only do what they are programmed to do. I love the game which is why I still want to play it. But I want to with other people!