This adapter is based on the ZyDAS ZD1211 chipset.
Mac OS X Drivers
Nevertheless, you can get the drivers here.
Hacking an External Antenna
Although the RF circuitry isn’t designed to handle a 2dB antenna, you can get a significant range boost via a very simple hack – just take 1.5cm (or so) of solid copper wire to form a little rod and solder it to the PCB antenna on the designated spot:
Make absolutely sure that you have enough of a connector surface to lend mechanical resistance to the join – otherwise, a lateral pull on the copper rod will tear the PCB along with the solder.
Finally, cut a small hole on the casing to let the wire protrude:
If you picked the right gauge wire, the antenna connector will grip the wire tightly enough to hold the whole assembly together:
Nevertheless, you might want to consider dabbing the connector with one or two drops of glue (with a glue gun) to make sure there is enough mechanical resistance to avoid tearing the PCB – especially since the weight of the antenna connector alone is far greater than the SMCWUSB-G’s.