I suggest that you examine this onine demo: http://demos.telerik.com/aspnet-ajax/controls/examples/integration/gridandwindow/defaultcs.aspx?product=window
It shows how a button (or a link, it does not matter to what element the onclick function is attached in the code-behind) can be used to open a RadWindow and pass to it the information about the chosen row. Then, when the popup is closed the grid is refreshed.
In the popup itself you can have whatever controls you need on the page, if you already have your upload module ready in a user control, simply loading it in the dialog pages should let it function.
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