Setup home network for 3 story cement building.
I am setting up a home network in Ecuador in a three story cement building. I have high speed fiber optic Internet service and from the main floor to the 2nd floor I get a fairly decent signal but the third is really low. I currently have a Linksys E900 wireless router provided by the ISP. I purchased one Airport Express and two AirPort Extreme devices from the US and brought them over. I do not have Ethernet cabling in the building so need to go the wireless route. What is the best way to set this up with the equipment I have? I assume I replace the existing wireless router with either the Express or one of the Extremes. Also the third level is a terrace with only half of it covered. the only thing I've tried so far was replacing the E900 with one of the extremes but the signal was actually a bit less and nothing at the terrace level which I did have a low signal before.