How to convert Unixtime to GMTime in SQL Server

SELECT dateadd(s, ,<YOUR DATE TIME IN UNIX>, '19700101')
eg.
SELECT dateadd(s, 1113211532, '19700101')

returns; 2005-04-11 09:25:32.000

Thanks Guys ...
I was using the below SQL to get the last 30 days data .. How can i use the same to get the last 30days data which has uNIX timestamp

SELECT ID Where Date >= DATEADD(D,DATEDIFF(DAY, 0 ,GETDATE())-30, 0)
and Date < DATEADD(D,DATEDIFF(DAY, 0 ,GETDATE()), 0)

I am sorry its the otherway .. I need to check GMT date against Unix Date by converting GMT to UNIX..

just reverse it:

DATEDIFF(s, '1970-01-01 00:00:00', UnixTime)

correction:

UnixTime  = DATEDIFF(s, '1970-01-01 00:00:00',MyTime)

SELECT
 *
FROM
 [YOUR TABLE]
WHERE
  Convert(datetime, dateadd(s, ,<YOUR DATE TIME COLUMN IN UNIX>, '19700101')) >= dateadd(dd, -30, getdate())

Thanks guys