Any ASX broker can set up an account for you and create a HIN. You will need to quote your SRN which is shown on your holdings statement sent by the registry on behalf of the company.
You can also sell your shares in a 'one-off' sale. Please note, one-off sales typically incur higher fees and it may be more economical to open an account with a broker.
If you do simply want to sell your shares as a once-off:
Refer to CMC Markets Stockbroking’s Sell Only Service and complete a One-Off Sale Facility form: http://www.cmcmarkets.com.au/en/stockbroking/sell-only-service.
e: brokingservice@cmcmarkets.com.au
p: 1300 360 071
Nabtrade also provides a one-off sale service:
p: 13 13 80
As does OpenMarkets. Their one-off sales page is found here.
p: 1300 769 433