Read Instructions Carefully
Modified Ralink USB Drivers
Took the latest Ralink USB Driver: USB(RT2870/RT2770/RT3X7X/RT537X) and added an entry for the Geetek Janus II RT2870.
USB(RT2870/RT2770/RT3X7X/RT537X) - 10/01/2012
The latest Ralink USB Driver dmg (direct from website)
W/ Added Geetek Janus II 802.11N
Connecting works but only through Ralink's Wireless Utility
Access point mode didn't work for me, the utility didn't seem to interface with Internet Connection Sharing right. I ended up enabling Ralink's ICS and manually bridging en0 and en2. (This is not a NAT)