I hope I have misunderstood what you needed, tell me.
.....chargeArray(1,4)
private function chargeArray(indexA:int,indexB:int):void
{
var myArray:Array = new Array();
var expenses:ArrayCollection = new ArrayCollection([ {Label:"Taxes", Value:2000},
{Label:"Rent", Value:1000},
{Label:"Bills", Value:100},
{Label:"Car", Value:450},
{Label:"Gas", Value:100},
{Label:"Food", Value:200},
{Label:"Taxes1", Value:2000} ]);
myArray = expenses.source.slice(indexA, indexB);
expenses.source.splice(indexA,(indexB-indexA));
expenses.refresh();
}