Ok - so I'm going to come at this from an angle you're not going to like. If there have been no breaches of the avo. As no not a single example where you contacted the cops because of an alleged breach, which they then investigated and charged the ex.... And a magistrate found the ex guilty... IF in that situation then good grounds for AVO to be extended. Not the case? doesn't seem to be based on the info provided, then nope, no need to extend the thing.
As you said a 'threatening look is hard to report'. Well the ex doesn't have to smile... Maybe you interpreted his threatening look - but he was tired, or bored and you (rightly) have some anxiety about this person and as such read his look wrong. But even if you didn't looking at you is not a crime.
Next - some people want an avo in place because they reckon it could help their cause in family law. Frankly, if extending avo's was easy then I reckon every applicant would do so regardless and the respondent would just have to suck it up OR blow $$ on solicitors over something pretty trivial, like being accused of a 'threatening look'. All the more the case if family law issues are in front of the court.
Next - You are still protected. just because the avo ends, doesn't mean the respondent can commit violencce. With the AVO on file the cops will take any complaint more serious.
Innocent until proven guilty? yeah, nope. With avo's most are 'accepted without admission'. So the ex has never actually been found guilty of anything. Innocent until proven guility? So the ex has had to deal with the avo even though he has not been found guilty AND you want those conditions extend when he has not been found guilty. OH, and that other great thing our legal system is meant to be predicated upon. Something about paying one's debt to society. So the whole idea that once someone has completed the terms imposed by a court they're a free man.
But since you've asked. What is the process. Well go to the local police station. Ask them. They might help. Probably wont. Especially if there are no breaches on file. Then go to the local court where the original matter was heard. The clerk of the court might help, or will direct you to a 'women's legal service.
Story time - I'm a bloke btw. I also had an avo on me and the fact that my ex used to punch me didn't seem to matter. So I accept without admission. Over the first 4 months I'm constantly called to the cop shop because she is alleging a breach. Once, she lost her car keys. She accused me of breaking in and stealing them. Cops call me, tell me if I don't come down to the cop shop (AGAIN) they will come to my workplace (I'm a teacher) and they will arrest me. WTF? So I have to walk out of class and go to the cops shop. On this instance I kinda lose it. I'm crying. I'm exhausted. Being questioned about her fcuking car keys.... I ask the cop, please call her up. Ask her if she found them. SHE HAD... The cops asked why didn't you call the police to notify us. Her answer? Forgot. Eventually the cops stopped investigating her bs. Sometimes they would call me to check I could prove I had been somewhere else OR they just called so they could tell her they 'investigated'.
Why the story? well look. I was actually the vicitim. She used the avo and every other bloody stunt - especially the kids to hurt me. She is just a horrible person. What I came to realise - Pay attention now, but what I realised was the law, police AVO's or any other bloody thing could not stop me feeling anxious / intimidated / threatened. So another example - She rocked up to change over and started throwing dirty laundry that she'd smeared in her own excrament at me. The clothes were the clothes the kids were meant to wear over the weekend. My nerves were shot. Now listen up because the lesson is about to arrive.... I changed my world. Instead of feeling threatened by her I taught myself to pity her. I made a conscious decision NOT to be scared. I refused to let myself feel weak or afraid. A funny thing happened. It took a while. But when I stood there, calm and proud and spoke confidently with manners SHE kinda started being a little bit nicer too.
Short version - I don't think the law can fix this one for you. Not without a whole lot of past breaches to justify extending the avo. But you can work on your attitude and stop being a victim.