Anything that's left, leave it there because even what looks like smokeable nugs has chlorophyll and the plant needs all the photosynthetic capability it can get!
Dig up as much of the surrounding soil as possible. You're going to have a monster root ball and you'll need a big pot for it... 2 1/2 feet is manageable though.
It won't produce a crop all year. You have to put it under 24 hour light to get it to go back into veg node.
Do a search on "re-vegging" and it will tell you everything you need to know.
One word of caution, the stress of digging up, repotting, revegging, plus moving indoors, plus if it was exposed to cold night temps... it is quite likely to die, so you might also consider starting a 'real' indoor grow.