Hi there,
Floorplanner is built to design and view each floor separately, not really for designing the house as a whole or the exterior. But what I would do if I were you, is upgrade to a Pro account for a month, then you can export each of your floors as a .kmz file. That’s a 3D file that you can import in Sketchup. Then, download Sketchup Pro, and import your floors in there. its quite a quick solution to add your floors together and add some textures and balcony and such to the outside.
see this page to upgrade to pro, and when you’ve upgraded and open your project, the 3D export option is under the first icon in the top right.