Need a router or access point

My internet access comes form a wireless signal broadcast in my town, which I pick up with an external antenna. I need an access point or router that can act as a wireless client and re-broadcast the wireless through my house.

Not sure why this is such a strange thing I am trying to do. Why don't the major manufacturers just include this in their existing hardware so you can select DSL, CABLE or WIRELESS as your internet provider?

What can you recommend I buy to make this work?

Right now the external antenna is connected directly into a dlink PCI wireless adapter card that has the standard dlink size connector for an external antenna.

Are you saying that if I buy a cable router with wireless that it will be able to connect as a client to the wireless signal and use it as the internet connection? Then I can just use an ethernet cable to connect to my computer/other wifi AP? If so, what are the leading cable routers out there?

Thanks for your help!