Yep, only the first 75 episodes were licensed in English, and Championship Road movie/ova. The company that licensed sort of went bankrupt or at least decided to stop releasing anime or something since there were losing money. No other company since then has decided to license it since the series isn't that popular at the time it came out.
So to enjoy rest of the series, you got to read the sub titles of it. Anyway, make sure you watch episode 76.
After that you have to start Hajime No Ippo: New Challenger (25 episodes), then finally after that. Hajime No Ippo: Rising (25 episodes). It's hard to believe,.
Its not dubbed, since it was DVD only content in Japan where the episode is 'filler' that doesn't really appear in the manga. For some reason when the company licensed it, they didn't know about episode 76, or it wasn't included in the deal. Nope, season 2 takes place where the movies ended. So New Challenger starts at volume 36 (?) and goes toward like volume 46 (?). There might be a recap at the start of the season, but you don't actually see the fight at the start.
Also, I think in the manga, Kimura vs Mishiba happens first, then Ippo has his title defense. But if you watch the movies, I think you need to watch Ippo's defense first, and Kimura's ova 2nd, where some events in the story was re arranged (or cut) in order to fit into a movie.