Some PCI wifi cards will work as an access point, but you will want to check for this before purchasing. I know the PCI wifi card that came with one of my Asus boards can actually work as access point and a client at the same time. In this situation, throughput will probably be halved each way, but that sounds like something you're willing to accept. It's been in the back of my closet since I have no use for it yet, but have considered it for my carpc. No idea if it actually works as advertised, but they do exist. There should be other cards that can do this too.