Yahoo is a Melbourne IT reseller.
http://www.melbourneit.com.au/policies/yahoo-gtld.php
You don't say whether it's a .com or .com.au. Regardless the domain would have expired more than 14 days ago, the registry hold time is longer than that.
How long do you expect them to hang on to a domain ? Yahoo, Melbourne IT is no quicker than anyone else to release domains that have expired.
Pays to keep up with your domains, there are plenty of cheap tools available which let you keep track of all your registrations.