2 router network

[Rixis]

simple enough question, not so sure on the answer (not had chance to fiddle yet but i garner it ain't too simple? /shrug)

My sister wants to run 2 wireless routers through her home, to get better coverage (3 floors, 1 router won't cover it all without buying a new one)

She has 2 routers, she wants one plugged in upstairs, one downstairs, for full coverage, i've checked google, but pretty much every solution requires having the second router hardlined into the first one and disabling a couple settings, but running a cable from downstairs to upstairs ain't really viable either

So is there anyway to plug in 2 routers off seperate phone points and have them setup to cover the entire house? she said she tried it and had some problems, but i think the problems were likely that her windows was connecting to the higher priority network in range, which happened to be the one with the weaker signal, and she wasn't able to connect to the other one (without fiddling i cannae be sure on this)

I'll get to fiddle with it tomorrow and see what i can see, but would like to be able to go there with a couple of ideas and solutions ready incase it's not what i'm thinking/able to fiddle about towards

[llDemonll]

You want something like a wireless repeater. A lot of routers can be flashed to have firmware that can enable functionality like this

[Deleted]

Look for WDS (wireless distirbution system) on both devices, if they're not too old, they should have it.
edit: You want LAN-type WDS. Apparently WPA2 won't work when using WDS, atleast on my dd-wrt router.. this is copied from my routers help:

WDS (Wireless Distribution System) is a Wireless Access Point mode that enables wireless bridging in which WDS APs communicate only with each other only (without allowing for wireless clients or stations to access them), and/or wireless repeating in which APs communicate both with each other and with wireless stations (at the expense of half the throughput). This firmware currently supports two types of WDS, LAN and Point to Point.
LAN-type WDS
This is the easiest, and currently most common, type of WDS used for linking LANs. It is very simple to setup and requires no extra routing protocols or knowledge of networking. Simply put, it is pure bridging. A simple example would be extending the range of an existing AP by setting up a 2nd AP and connecting it to the first using LAN-type WDS.
Make sure you are using the same Wireless Settings on both routers and not any type of Wireless Security.
Find a drop-down selection that has Disabled displayed. Click this and select LAN, do the same on the other router.
On the first router, take the numbers next to Wireless MAC and enter them in to the second router on the same line that you set to "LAN".
Take the Wireless MAC from the second router and enter them on the first router.
Check for any typing errors and then click Save Settings.
Go to the Wireless Status page. You should see WDS Link and the Wireless MAC of the other router listed, with a signal reading. If the signal is "0dBm" then there may be something wrong. Check your antenna connections and configuration settings, and try again.
Once you have a good signal (-70dBm to -30dBm, -70dBm being lowest), you can change the Internet Connection Type on the Basic Setup page of the second router to Disabled and set the Gateway to the LAN IP Address of the first router. You can now run normal tests to check if you are connected (like ping).


Note
WDS is only available in AP mode. Also Wireless encryption WPA2 and Wireless network mode B-Only are not supported under WDS.