In newer apartments, there are already network cables running to all the rooms. They end up in a "patch panel" which is just a cabinet box normally located near the entrance. Each network cable ends up in a data point or ethernet port in the rooms. I guess yr place dont have them so it's not relevant. If u want to know what a patch panel looks like, u can go to this link:
http://www.patnotebook.com/bto-networking-singapore/
As for using 2 routers it depends on what u r trying to achieve. If there are no blind spots but u r just unhappy with the wifi performance of the 868, u can just replace it with a more powerful router. But if there are some areas that are not receiving wifi, then u can consider getting a 2nd router and setting it up as an Access Point ("AP").
To set up the AP on the 2nd router, this is what u need to do:-
- connect the new router (ant LAN port) to a desktop/laptop using cable
- start a browser and go into the Settings page of yr AP router and make sure that the LAN IP address is in the same network as yr 868. For eg if yr 868 is 192.168.0.1 then make sure yr AP router is 192.168.0.x where x is between 2 to 255
- look for the DHCP settings page and DISABLE DHCP on the AP router
- set yr SSIDs and passwords for yr AP wireless bands
- connect an ethernet cable from any of the LAN ports on the 868 to any of the LAN ports on the AP router.
That's all!
Yr devices will now be able to connect to the new wifi networks from yr AP router. If u do not need the wifi networks on yr 868 router, u can turn them off. If u leave them on, make sure u select different channels for both routers to avoid conflict
Aside from AP mode, u can also connect the 2nd router as a Wireless Bridge or as a Wireless Repeater. For these 2 modes, u dont need to run a cable from the 868 to the 2nd router - the 2nd router will link up wirelessly. Of course, the connection will not be as good as the AP method which is wired.
For Wireless Bridge, the 2nd router is effectively acting just like a USB adapter. It receives the inward data and passes them onto devices that are connected to it using cables. There is no wifi from the e2nd router.
For Wireless Repeater, the difference is, there IS wifi but bandwidth is halved for wireless clients.
Hope the above is clear enough