URGENT- t-SQL SUM problem

Hello Experts
I have inserted a table structure, some data and my query as below.
But there is a problem on line:
SELECT  m.smodel,c.smodel AS col,m.lIlaveMaliyetTutar * c.lbrutfiyat/1000 AS RESULT

I want to replace the value as SUM(lbrutfiyat). Because this value is the sum of lbrufiyat columns for a specific lfisno.

Please help

create table erdem_fistipleri2
(
smodel varchar(50),
lfisno varchar(50),
nstoktipi int,
sfistipi char(50),
lbrutfiyat float,
lIlaveMaliyetTutar float
)
******************************************************


INSERT INTO erdem_fistipleri2 values('XXXXXXXX','9999999',2,'FA',1,166.67)
GO 
UNION ALL
INSERT INTO mytest values('159 010 100','9999999',4,'HA',100,0)
GO 
UNION ALL
INSERT INTO mytest values('159 010 106','9999999',4,'HA',500,0)
GO 
UNION ALL
INSERT INTO mytest values('159 010 105','9999999',4,'HA',400,0)
GO 
UNION ALL
INSERT INTO mytest values('YYYYYYYY','9999999',2,'FA',5,833.33)
GO 
***************************************************


SELECT  m.smodel,c.smodel AS col,m.lIlaveMaliyetTutar * c.lbrutfiyat/1000 AS RESULT
INTO #subresults
FROM    erdem_fistipleri2 m
CROSS APPLY 
(
        SELECT  smodel,lbrutfiyat
        FROM    erdem_fistipleri2 c
        WHERE sfistipi='HA'
)c
WHERE m.sfistipi='FA'