You will need a wi-fi bridge. This is something you connect directly to your network JUST FOR THE SETUP then you can plug it in anywhere in your home and plug your non-wifi products into it and get wi-fi access.
Something like this will give you one computer connection...
http://www.newegg.com/Product/Product.aspx?Item=N82E16833124015
But I would go with something like this...
http://www.newegg.com/Product/Product.aspx?Item=N82E16833124266
The second one gives you connectivity if you add more Ethernet products to your equipment stack and need networkability. Something like AppleTV or something else can then be added easily.