It sounds like you're after this? Alternatively, this.
By the looks of it, the former will have your PCs connected to the same network as the one on the other side of the air link - it'll all be bridged together as a single subnet. While the second one will have your little PC collection as being on a different subnet, and have everything routed and NATted via the primary network into the Internet. It's up to you which one suits your situation better (but probably the first one). Either way, you'll end up with your secondary wireless box acting as a wireless adapter, rather than an AP.