There is no problem with the location you at at, the problem is with the farmer you are working for.
Don't waste your money moving to another town or state. Take the day off and get a pushbike or car and goto every grape farm/vinyard and say your looking for grape picking work. Your in the correct spot just on a crappy farm. Look below:
Fruit Picking Mildura, this area is one of Australia's major food bowls providing:
* 95% of dried grapes
* 69% of table grapes
* 55% of almonds
* 41% of pistachios
* 33% of olives
* 24% of carrots
* 23% of asparagus
* 21% of wine grape crush
* 20% of citrus
* 11% lemons