Newbie here. I recently bought a Marin Portofino road bike. I discovered it was lacking in hill climbing ability due to the gearing (12-24 8-speed rear). So I bought a larger cassette (11-32), without realizing that the max capacity on the Sora rear derailleur was 27t. This bike uses the (sorry I don't know the correct term) shifting apparatus where you push the brake lever levers inward to shift. I searched Shimano's website to see if I could find a compatible rear derailleur that would accomodate the larger sprocket on the cassette (32t maximum), but the largest I could find for any of their road products was the same as the Sora (27t). I'm sure there's a good reason for that, but I don't know what it is.
In the MTB section of their website I did find derailleurs that would accomodate the larger sprocket sizes (like the Deore LX line), but I don't think they are compatible with the road-style shifters on my bike (I'm not sure about that though). I'm under the impression that the road-style shifters on my bike require a type of derailleur that works with them, and they are different than MTB bikes use.
I'm hoping someone with some expertise on the forum here can give me some advice/guidance as to how I can best accomplish making my bike more hill-worthy. This whole cassette / derailleur issue is confusing (and expensive).