Using Stored Procedure In Report Designer

I have the following stored procedure. I have a few questions regarding its use in Reporting Services.

1) Invalid Object ##Tmp_Table1, this prevents the report designer from displaying the available fields.
2) The @totalcount isn't available (I need this value for a calculated field in the report)
3) How would I go about creating dropdowns/calendar controls for users to fill in the parameter values?

ALTER PROCEDURE [dbo].[spTermCodeReport]
@tablename char(12) = 'results_NAF',
@source varchar(20) = 'AmExpProvList',
@sourcedate datetime = '05/30/2007',
@TotalCount int = 0 OUTPUT
AS
DECLARE @SQLString varchar(255)
BEGIN
SET NOCOUNT ON;


SELECT @SQLString = 'SELECT count(*) AS TRCount INTO ##Tmp_Table1 FROM ' + @tablename + ' WHERE source=''' + @source + ''' and sourcedate=''' + convert(varchar(10),@sourcedate,110) + ''''
EXEC(@SQLString)
SELECT @TotalCount = TRCount FROM ##Tmp_Table1
DROP TABLE ##Tmp_Table1
SELECT @SQLString = 'SELECT termcd, count(termcd) AS TermCDCount FROM ' + @tablename + ' WHERE source=''' + @source + ''' and sourcedate=''' + convert(varchar(10),@sourcedate,110) + ''' GROUP BY termcd'
EXEC(@SQLString)
END