That's a very good shot! You have both a half-height slot and a full-height slot. The half-height slot is only meant for half-height cards; note the location of the black hold-down screw.
The full-height slot may have special requirements or not support arbitrary mini-PCIe cards; some are meant for SSD cards. There's a second slot in the Acer D250 which I tried with a second Atheros card. It never connected, like there was no signal. Maybe a problem with the antennas I was using, but there have been similar reports, even one in the threads I saw about your Broadcom yesterday.
The second eBay link from earlier claims to be an AR5BXB63, although it seems a bit pricy.
Can probably find one for about the same price as a movie, and it may provide at least as much entertainment even if it doesn't work.