Shafted by Toyota-what next??

Its a long winded story but here goes.
We bought our 2003 GXL HZJ105 cruiser(62000kms) at christmas with one year factory warrenty left.On the drive home it coughed and splutted and blew heaps of black smoke out then cleared and ran perfect(lasted maybe two seconds) but over next couple of days noticed a surge at light throttle aplications.I contacted toyota and booked it in for the pump to be checked.A week later we got it back,surge was gone but still not happy with amount of smoke it was blowing and when warm it would take 4 to 5 cranks before firing up.Again it went back to toyota who checked it out and said all was fine.We left tassie that week heading for Kununurra and on our way through Alice we called into Toyota to see what they had to say about it.They said definatly something wrong with pump but it would take two weeks to do.As we had to get up here for work we decided to get it done up here.Yesterday I got a call to say the pump had dirty fuel go through it and it and injectors would need full rebuilds at a cost of $4700,no warrenty as they dont cover dirty fuel problems.So I contacted toyota back in tassie who after lengthy discussions decide to pay half.So I ask who is paying other half as I am not.After being fobbed of to about 4 people we hit a stale mate.I say problem was there from the start,they say we got dirty fuel on way up.When pump was done in tassie it was not fully disasembled,only fuel pressures were re set and pump put on test machine and ran.I have contacted Toyota australia who havent got back to me yet,consumer affairs said to take half and be happy,yeah right .
So who else can I contact to get a end to this.Wish I still had our 4 Runner.By the way our vehicle has been off the road for 4 weeks now.