WiFi Access Point form Ethernet?

Right so bascially I have an Ethernet cable running from the Home Hub Router to a room far away, but wanted some advice on how to create another WiFi access point at the end of this cable. To help I drew a lil' diagram


via s23.postimage.org

The bit circled in red is what I want to make into an access point :)

Sorry for being so confusing, I myself am very confused, but thanks!