If the macro is putting the data into the column - test the data before it is placed in the column.
If IsNumeric(YourData) Then
'its numeric - so save it
ActiveSheet.Range("A1").Value = YourData
'its not numeric so send a message
MsgBox "This is not a number"
For emailing from Excel you can look at response #1 on this thread, or look at these articles on MSDN.