It should be rooted from factory as I understand.
This might not appear to be the case because you may not have installed the Super User app, but if you download that from the Google Play store, then I would recommend trying Avast again to see if it work for you then...
I would then recommend a full PC backup, making it viable to load from the Micro SD card.
Also a word of caution: You need to keep an eye out with the ROM Manager and C.W.M.
The clockwork is specific to the device, any crew ups here and you will render the device obsolete.