Stored Procedure Help Please

Parameters to be given at :
Resolution Time
Interface
MONTH

select ref_num,opened,closed,agent,grp,subteam,team,organization,datediff(Hour,opened,closed)as TTR, 
(cast(isnull(month([closed]),'') as NVARCHAR(2))+'-'+isnull(DateName(month,[closed]),'')) as [Month],ResolutionTime=
(CASE 
WHEN datediff(HOUR,opened,closed)between 0 and 24 THEN   '1. Less Than 1 Day'
WHEN datediff(HOUR,opened,closed)between 24.1 and 48 THEN   '2. 1 - 2 Days'
WHEN datediff(HOUR,opened,closed)between 48.1 and 84 THEN   '3. 3.5 Days'
WHEN datediff(HOUR,opened,closed)between 84.1 and 120 THEN   '4. 3.5 - 5 Days'
WHEN datediff(HOUR,opened,closed)between 120.1 and 240 THEN   '5. 5 - 10 Days'
WHEN datediff(HOUR,opened,closed)between 240.1 and 720 THEN   '6. 10 - 30 Days'
        ELSE '7. More Than 30 Days'
   END),
   Interface=
   (CASE
WHEN Created_via = '3550' THEN 'Email'
WHEN Created_via = '3554' THEN 'Calls/Chats'
WHEN Created_via = '3556' THEN 'Web Forms'
WHEN Created_via = '3570' THEN 'Auto-Generated'
else 'Other'
END)
   From call_req_IT
   where
   YEAR(closed) = YEAR(getdate())