EXEC master.dbo.sp_configure 'show advanced options',
 1 RECONFIGURE EXEC master.dbo.sp_configure 'xp_cmdshell',
 1 RECONFIGURE EXEC xp_cmdshell 'bcp "SELECT * FROM tbl WHERE YEAR(CAST(SUBSTRING([myDateString], 7, 4) AS DATETIME)) = 2013;"
   queryout "\\myserver\public\tkt.txt" -T -c -t;'

SELECT * FROM tbl WHERE YEAR(CAST(SUBSTRING([myDateString], 7, 4) AS DATETIME)) = 2013;

SELECT * FROM tbl WHERE CONVERT(datetime, [myDateString], 103) > DATEADD(day, -3, getdate())

> 

[SQL] SELECT * FROM tbl WHERE CONVERT(datetime, [myDateString], 103) > DATEADD(day, -3, getdate())

[Err] 22007 - [SQL Server]Conversion failed when converting date and/or time from character string.

SELECT * 
FROM tbl 
WHERE CAST(SUBSTRING([myDateString], 1, 10) AS DATETIME) >= DATEADD(d, -3, getdate());

[SQL] SELECT * FROM tbl WHERE CONVERT(datetime, [myDateString], 103) > DATEADD(d, -3, getdate())