Detective Sergeant Heath Jones is also seeking information about a pistol and silencer used during the assault. The gun was found in the Pandora area near the Bluewater Hotel after the assault.
Mr Jones said the attack appeared to be drug-related.
"We are very keen to find both Johanna Peterson and Patrick Haywood, as well as identify where the pistol came from and who owns it. This was a particularly violent assault and the victim suffered serious head injuries.
"Someone will know where these two people are and where the pistol came from. We are keen to speak to anyone who knows anything about this incident."
Police consider Haywood and Peterson to be dangerous and should not be approached. They believe another pistol was used in the assault and the pair may have it with them.
"Two people have already been arrested in relation to the assault and they are currently facing charges of aggravated burglary and wounding with intent to cause grievous bodily harm," Mr Jones said.
The victim of the assault was now recovering at home after a short stay in hospital.
Police would not provide any more details about the incident as it was now before the courts and investigations were ongoing.
Anyone with information about Peterson and Haywood or the pistol should contact Mr Jones at HB Police on 06 8310700 or information can be left anonymously on Crimestoppers 0800 555 111.
