Test it as follows:
print [dbo].[myCalendar] (getdate())+ CHAR(13)
print [dbo].[myCalendar] (dateadd(month,+1,getdate()))+ CHAR(13)
print [dbo].[myCalendar] (dateadd(month,+2,getdate()))+ CHAR(13)
print [dbo].[myCalendar] (dateadd(month,+3,getdate()))+ CHAR(13)