Ajaxtoolkits Piechart

Hi guys.. not sure why the pie chart show not properly. 

Meanwhile... 
1) how do i change background color of each value from codebehind? TQ
2) can i show USD1,340 instead of 1340 in my piechart?

CURRENT RESULT


CODE BEHIND

    Private Sub BindChart()

        Me.PieChart1.PieChartValues.Add(New AjaxControlToolkit.PieChartValue() With { _
            .Category = "Income", _
            .Data = "2580.00" _
        })

        Me.PieChart1.PieChartValues.Add(New AjaxControlToolkit.PieChartValue() With { _
            .Category = "Expenses", _
            .Data = "1340.00" _
        })

    End Sub

HTML MAKRUP

<cc1:PieChart ID="PieChart1" runat="server" ChartHeight="300" ChartWidth="300"  ChartType="Column" ChartTitleColor="#0E426C"></cc1:PieChart>