Networking – Adding a second wifi router / wireless access point

DD-WRT will fix all those limitations you speak of. Here's a diagram of how it works:

Here are the details of the wireless bridging with dd-wrt.

The tutorial you have followed specifically refers to connecting the two routers with a cable. They've suggested a power line connection as an alternative, but it amounts to the same thing here.

The majority of WiFi routers only operate their WiFi system as an access point. PCs, WiFi printers, smartphones, etc all operate as clients connecting to an access point. This means that you cannot connect two routers using the Wifi interface.

If you're running the DD-WRT firmware on your router it is possible to configure it to operate as a client and connect to an access point just as a PC would. In this case, though, the WiFi connection is no longer functioning as an access point so your PCs won't connect to it wirelessly - you have to use a wired connection from the PC to the second router.

Alternatively, you could add two new access points both configured to operate as a wireless bridge, plug one into the wired port on your first router and plug your second router into the wired connection on the remote access point. This works well (I had a similar set-up running for some years) but it means additional hardware.

For your requirement a long cable is probably the most cost effective solution, if you can find a way to run it between the two locations.