Now is actually a very good time to visit Norway, as the NOK has fallen significantly recently against USD and EUR.

Two days is good for Bergen, but as most people going there use it as a base for seeing the fjords I would perhaps go for Oslo instead. Both CPH and OSL has more than enough to fill more than two days, so choosing CPH for having more to see is not that important for such a short visit. The compulsory "Oslo-sights" (Munch, Viking ships, Vigelandsanlegget", the new Opera House) will more than fill the available time.