To remove .rpt from crystal reports export try this:
Dim formats As Integer
formats = (CrystalDecisions.Shared.ViewerExportFormats.AllFormats Xor CrystalDecisions.Shared.ViewerExportFormats.RptFormat)
CrystalReportViewer1.AllowedExportFormats = formats
'Or Shorter Version :
CrystalReportViewer1.AllowedExportFormats = (CrystalDecisions.Shared.ViewerExportFormats.AllFormats Xor CrystalDecisions.Shared.ViewerExportFormats.RptFormat)