He attempted to pull down her leggings and she tried to pull them up. He forced his hand inside her leggings.
She had difficulty breathing as Pullan was on top of her.
"She was so petrified she urinated," Judge McGuire said.
The victim managed to get to her feet but Pullan was still holding her. The woman bit Pullan on the hand as she struggled to get away from him and then he ran off. The entire attack, which lasted two minutes, was caught on closed circuit television (CCTV).
On September 5 Pullan handed himself into police after seeing CCTV footage of himself in the media.
Judge McGuire said the victim suffered a number of bruises and cuts during the attack and was unable to work the next day.
She was now a lot more wary and since the attack a lot of the victim's hair has fallen out and she has not had a full night's sleep.
"It must have been the longest two minutes of that victim's life. It's little wonder that as a shock reaction she is losing hair."
Judge McGuire said Pullan said he could not remember the incident. However, Judge McGuire said he did not accept that and neither did the victim.
The victim had said if Pullan was calculated enough to follow someone down an alleyway he must have been able to recall what happened, Judge McGuire said.
In an effort to stop late night violent attacks the people of Taupo had installed CCTV cameras, Judge McGuire said.
"It's a matter of great concern that even with that ... serious offending continued."
Judge McGuire said Pullan had said that he been drinking that night and had "snorted a few lines". Pullan had previous convictions including one for unlawfully on a property in Blenhiem, which had involved following a woman, Judge McGuire said.
The starting point was four years' jail but was reduced to three years' jail to give him credit for his guilty plea and his remorse which he had expressed through a letter to the victim.
Pullan's lawyer, Katherine Ewen, said her client did not have any memory of the incident but he knew it was him who had committed it. The offending was out of character for him.