Bill,I am doing the same thing it is the cat'sass , just take the filter from the grid and apply it to the reports filter string property this will filter the report, something like below, also you can get snazzy and allow the user to save the filter and then create their own list of saved filters so they can simply choose from a list and apply whatever saved filter fits the bill or create a new one.
Dim
lcfilter As String = Me.GridView1.ActiveFilter.Expression'Set filterxtrareport.FilterString = lcfilter