Bluetooth, WiFi, and GPS are all big power users. I dont know about the auto-on, but a relay can take 400mA easily depending on the size (or it could take 50mA again depends).
I think you have actually surpassed the cutoff for getting a powered hub.
Since it is a laptop, you cant even distribute the usb to not overload any root since the laptop only has 1 root (driver, not physical ports).
I say get a powered hub. Or at the least, some of those car chargers for mp3 players/cell phones that have a USB port on the other end so you can splice power off of that, and data through the unpowered hub as normal. And keep in mind the hub itself does use a little power.