Connecting 2 mixed networks(with wifi and ethernet stations)

I've got a home network with both wifi and ethernet clients(2 pc's with 2
wifi cards and 2 pc's with ethernet cards + a soft AP--HostAP under linux- +
a soft linux router for connection to the Internet). This configuration
works fine and all the machines have access to the Internet and can share
files and printing.
I intend to replace the HostAP PC with an AP(a Dlink-900AP+) and I hope
everything will work as before with the right configuration.

Now I've got a friend about 500m away(line of sight) and he's got roughly
the same type of network.
The question is: How do we connect the 2 networks so that they become
virtually one?
I was thinking of configuring the 2 AP's in bridge mode but after reading a
few docs on the Net I learned that the wireless clients would then not be
able to communicate with each other, at least not in infrastructure
mode(bridges only merge two wired Lans!).
Then I thought that maybe setting up one AP in AP mode and the other in
Repeater mode would solve the problem. It seems this would then eliminate
the wired clients.

Is there a solution? I've heard there're some AP's which can be configured
in both AP and Bridge mode simultaneously. What're they? Has anyone been
confronted with the same problem and how did they solve it?

Your answers are eagerly awaited.

Mathias