From my experience, maps are hard to come by in Havana. If you need a professional map, your best bet is to buy one (probably online) before you leave. But they don’t come cheap.
My advice would be to simply print out a map from this website. You can see here (http://bestcubaguide.com/best-havana-map/) the map that I always use when I am in Havana. It’s easy to read once printed out and it has all of the most common streets. You should be able to get around fine with this map.
As for CADECAs, I don’t think there is a map which lists all of them. But you really should not have trouble finding a CADECA. There are hundreds scattered all over the city. And once you change a few hundred dollars, you won’t need more money for a while. There are a few CADECAs on 23rd street and you will find them at most large markets. In Old Havana there are a few on the popular tourists streets (Obispo) and another near the Old Square. Basically, if you keep your eyes open for a CADECA, you will find one. No map needed.