The Pi's weakness is it does not cope with usb will.  You need a 5v 1a psu for the Pi.  The Pi uses .500Ma for the cpu and .170Ma for each usb port.  What ever hub you use must have a psu that can supply a minimum of .500Ma to each hub port that is being used.

You should have a dedicated psu for the Pi, a dedicated psu for the hub.  Plug everything into the hub and then the hub to the Pi.  A wireless dongle can draw over .750Ma.  I never achieved good results using a wireless dongle and the Pi, much better speeds with cat5 cable.

I'm running 9 hubs with 100 erupters plus 2 Blades off the Pi and getting 53+Ghs, Minepeon under Arch & bfgminer.