After a while I ended up trying out dmmarck's suggestion and followed these steps:
15) To root your device, type the following code into the terminal, hitting return after each line:
chmod +x install-superboot-mac.sh
./install-superboot-mac.sh
16) The terminal should say:
downloading 'boot.img'... OKAY
booting... OKAY
17) You will now see the black Google screen with the lock icon at the bottom
18) Your phone should reboot automatically after a couple minutes on the Google screen. If, and only if, your phone doesn't reboot automatically after 5 minutes, unplug the usb cable and perform a battery pull
19) Put your battery back in if necessary and power on your device
20) Be patient while it boots up, and don't worry - first boot may take up to 5 minutes (as sbenson suggests, remember to breathe!)
21) You will need to set up your phone now and log into Google, etc.
22) Confirm Superuser app in your app tray
This worked. Thank you both for all of the help. Now I'm going to try and install 4.0.4 and see how that goes.
Wish me luck!