Put All The Day Monday'S Next Month + Add This Last Monday ?

i have this FUNCTION
and the FUNCTION work OK
now how to add to this FUNCTION another mondy date ?
"last month last monday"



Code Snippet
CREATE FUNCTION [dbo].[Monday_List]( @arg_date datetime )
returns table
as
return
(
select convert(varchar(10), (dateadd(mm, datediff (mm, 0, @arg_date), 0)
+ (8 - datepart(dw, dateadd(mm, datediff (mm, 0,
@arg_date), 0))) % 7) + offset, 103)
as Date,
[Index],
Number
from
( select 1 as Number, 'First_Monday' as [Index], 0 as offset union all
select 2, 'Second_Monday', 7 union all
select 3, 'Third_Monday', 14 union all
select 4, 'Fourth_Monday', 21 union all
select 5, 'Fifth_Monday', 28
) x
where month(dateadd(mm, datediff (mm, 0, @arg_date), 0)
+ (8 - datepart(dw, dateadd(mm, datediff (mm, 0,
@arg_date), 0))) % 7)
= month((dateadd(mm, datediff (mm, 0, @arg_date), 0)
+ (8 - datepart(dw, dateadd(mm, datediff (mm, 0,
@arg_date), 0))) % 7) + offset)
)


this is the Output i get



select * from Monday_List('1/3/8')

Date Index Number
---------- ------------- -----------
03/03/2008 First_Monday 1
10/03/2008 Second_Monday 2
17/03/2008 Third_Monday 3
24/03/2008 Fourth_Monday 4
31/03/2008 Fifth_Monday 5
*/


now i need to add to the FUNCTION "last month last monday"
like this


select * from Monday_List('1/3/8')

Date Index Number
---------- ------------- -----------
04/02/2008 last monday 0 ---------------------- i need to add
03/03/2008 First_Monday 1
10/03/2008 Second_Monday 2
17/03/2008 Third_Monday 3
24/03/2008 Fourth_Monday 4
31/03/2008 Fifth_Monday 5
*/

------------------------------
TNX