Taylor Riley :
Rogue Leader :
If you're going to run a wire may as well run one to another access point. It depends which type/brand of extender you are talking about. The thing i linked is a Wireless access point that requires a PoE switch, so at this point not what you want.
Define wireless access point? Is it simply like making Wireless Network #2 that runs off of the same router? So you just change the connection depending on what side of the house you are on?
So if you're looking to extend your network (for a low cost) the best way to do it is to have a wireless router, and run a ethernet cable to another router or wireless access point. WAPs are generally cheaper, they don't do any routing they just provide wireless access. Ignore the one I showed you before, instead something like this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16833704049&ignorebbr=1
You configure it with the same SSID and security as your router's wireless network, and it provides wireless signal from its point. Its basically the same thing as how wireless works in a business, they just have a lot of those WAPs around, with the routing done by 1 central router.
Slightly more technical but when configuring it you want to set the channel on the router and the WAP to different numbers, spaced from eachother (like 2 and 11) so they don't interfere with eachother.
You could do this with 2 airports as well, just turn off routing on the second airport, configure the wireless network like I said above, and it will behave like a wireless access point.