When everything has been absorbed (the saffron may not be uniformly distributed by now), add the broth (you have made - or rewarmed - it in another pot. It has to be hot). Definitely increase the heat (if you use an electric stove you should have increased it before so that it is now hot. Italian cuisine is simply not really possible with electric stoves, which are very much disliked among Italians, but anyhow...) Don't give up stirring! Now the saffron has to be uniformly distributed and the whole should be bright yellow. If the rice becomes too dry, add more broth and keep stirring.
After approximately twenty minutes, add the rest of the wine and remove the pot from the fire/source of heat. Now for the difficult part: you have to add the rest of the butter and the grated parmesan cheese so that the final texture is "just right": this means, it has to be definitely not a mush, but the individual grains should be linked together... well this is achieved by adding some parmesan, then some butter, then some parmesan again and so on. Tradition says that you have to draw exactly 36 circles while stirring in this phase (which is called "mantecatura," by the way).
You may then add pepper and embellish the whole with parsley. It has to look as a big yellow mountain when you serve it. eating, every guest can add more parmesan (or salt, or pepper) according to their taste.