good timing love - we have just been through the whole DX with my DS1 for auditory processing disorder
we self referred to an audiology clinic that does specific auditory processing testing- it was 2 x 90 minute sessions that cost us $200

it showed that my DS hearing was fine but he has trouble processing different sounds and where they come from so we had to buy him a headset like they mentioned to you! Mind you it was $2,300 and no funding available. The school could have got funding for next year for the set but that would be another whole year wasted so we are trialling it at the moment for 2 months to see if it makes a difference
DS also has trouble with the connections between the two spheres of the brain. One side takes the info in and the other acts upon that info, but the connections arnt there between both sides so he knows what he is suppose to do, but struggles on how to do it!
Therapy is to come and that is with a speachy who does APD therapy- some easy things they said that we can do a home for therapy include singing ( APD kids struggle to put words to a tune) and drawing and colouring in the same picture
DS also has an extremely poor working memory so that doesnt help at all and we suspect some mild dyslexia
we are also paying an aide 4 hours a week to work with our son- we have applied for funding several times but unfortunately in VIC the criteria for funding is crap and he misses out.
hope this info helps and if you want anything else please feel free to ask away or PM me if you want
the main thing with kids with APD is breaking the tasks down into easier steps for them to process!
HTH
mwah