Try to do this

--> Create temtp table

CREATE TABLE #Test(MonthOfYear int, Year int, Account int,Name varchar(255))

INSERT INTO #Test

VALUES(1,2013,1,'A')

INSERT INTO #Test

VALUES(12,2012,4,'B')

INSERT INTO #Test

VALUES(1,2013,4,'C')

INSERT INTO #Test

VALUES(1,2012,1,'D')

INSERT INTO #Test

VALUES(1,2013,5,'E')

--Build dynamic sql

DECLARE @Month int, @Year int, @account varchar(255)

,@sql varchar(1000)

,@DBName varchar(100) ='TEST'

-->Search single value in @account

SELECT @Month = 1, @Year = 2013, @account ='1'

SET @sql = '

SELECT MonthOfYear, Year, Account,Name

FROM #Test

WHERE MonthOfYear ='+CONVERT(varchar(2),@Month)

+' AND Year = '+CONVERT(varchar(5),@Year)

+' AND Account IN('+@Account+')'

PRINT @sql

EXEC ('USE '+@DBName+ @sql)

--> Search mutilple values in @account

SELECT @Month = 1, @Year = 2013, @account ='1,4'

SET @sql = '

SELECT MonthOfYear, Year, Account,Name

FROM #Test

WHERE MonthOfYear ='+CONVERT(varchar(2),@Month)

+' AND Year = '+CONVERT(varchar(5),@Year)

+' AND Account IN('+@Account+')'

PRINT @sql

EXEC ('USE '+@DBName+ @sql)

DROP TABLE #Test