Anatoliy,
You could just add oApp.Chart.Export(...) to the bottom of your code and take out the copy method and be done with it without the need to call anything else external. Something like:

oApp.Chart.Export("\images\temp\"+output+".GIF","GIF")

. Just need to get the objects and method names right.
>Run the following code, which creates several Excel objects and buidls a simple chart:
>

>CLEAR
>CLEAR ALL
>
>#DEFINE xl3DPieExploded    70
>
>PUBLIC oApp, oBook, oSheet, oChart
>oApp = CreateObject('Excel.Application')
>oBook = oApp.Workbooks.Add()
>oSheet = oBook.Sheets(1)
>
>WITH oSheet
>	.Range('A1').Value = 'Grocery'
>	.Range('A2').Value = 'Insurance'
>	.Range('A3').Value = 'Car lease'
>	.Range('A4').Value = 'Home Mortgage'
>	.Range('A5').Value = 'Hydro bill'
>	.Range('A6').Value = 'Water bill'
>	.Range('A7').Value = 'Other bills'
>
>	.Range('B1').Value = 559.33
>	.Range('B2').Value = 410.00
>	.Range('B3').Value = 254.44
>	.Range('B4').Value = 1631.56
>	.Range('B5').Value = 143.05
>	.Range('B6').Value = 84.15
>	.Range('B7').Value = 169.00
>	
>	.Range('A1:B7').Select
>ENDWITH
>
>oChart = oApp.Charts.Add
>WITH oChart
>	.ChartType = xl3DPieExploded
>	.Select
>ENDWITH
>
>oApp.Selection.Copy
>oBook.Close(0)
>oApp.Quit
>

>
>If no errors happened, you have an image of created chart in the clipboard. Open any graphics application (like Paint) and do Paste command.