I know the main track was closed after a lethal freak accident.
I don't need anything big though. It's just been my dream to go go-karting.
Are there any options, and what are the prices?
There are none left after the ones in Kai Tak and Diamond Coast closed in Kong Kong. you will have to go to China or Macao.
In Macao there is one the Cotai strip behind the golf court. I have however never been there and could not find an email/website either.
You might want to ask the HK club for further info: http://www.hkkartclub.org/
Chances are however, that you will not get very far with English on either of them.