Create table #foo
(
[User] char(2),
MemberID char(5),
ClubID char(2),
FamilyID char(2),
MemAmnt money,
AdditionalAmnt money NULL)


INSERT INTO #foo

SELECT 'U1', 	 'A1234', 	 'C1', 	 'F1' 	,100,	10 UNION
SELECT 'U1', 	 'A1234', 	 'C7', 	 'F2' 	,150,	10 UNION
SELECT 'U1', 	 'A2233', 	 'C2', 	 'F3' 	,150,	NULL UNION

SELECT 'U2', 	 'A1244', 	 'C2', 	 'F4' 	,200,	20 UNION
SELECT 'U2', 	 'A1245', 	 'C3', 	 'F5' 	,200,	NULL UNION
SELECT 'U2', 	 'A1246', 	 'C4', 	 'F6' 	,100,	10 UNION

SELECT 'U3', 	 'A1251', 	 'C5', 	 'F1' 	,100,	NULL UNION
SELECT 'U3', 	 'A1252', 	 'C6', 	 'F1' 	,100,	NULL  


;WITH t1 AS
	(SELECT [USER],[MEMBERID],SUM(MemAmnt) as TotalContribution
	  FROM #foo 
	  WHERE AdditionalAmnt >0
	  GROUP BY [USER],[MEMBERID])
 , t2 AS
	(SELECT [USER],COUNT(*) as NumMembers
	  FROM #foo
	  GROUP BY [USER])

SELECT #foo.*
	   ,TotalContribution = COALESCE(t1.TotalContribution,0)
	   ,TotalContributors =t2.NumMembers
	   ,giftValue = CASE WHEN t1.TotalContribution between 1 and 100 then '01'
						 WHEN t1.TotalContribution between 101 and 300 then '03'
						 WHEN t1.TotalContribution between 301 and 500 then '10'
						 WHEn t1.TotalContribution> 500 then '20' ELSE NULL END
FROM #foo LEFT JOIN t1 on #foo.[USER] = t1.[USER] and #foo.MemberID = t1.MemberID
		  LEFT JOIN t2 on #foo.[USER] = t2.[USER]

Drop Table #foo

Poor planning on your part does not constitute an emergency on my part.

SELECT *,
CASE WHEN TotalAdditionalContribution BETWEEN 1 AND 100 THEN '01'
     WHEN TotalAdditionalContribution BETWEEN 101 AND 300 THEN '05'
     WHEN TotalAdditionalContribution BETWEEN 301 AND 500 THEN '10'
     ELSE '20'
END
FROM
(
SELECT *,
SUM(CASE WHEN AdditionalAmnt  > 0 THEN [Mem.Amnt] ELSE 0 END) OVER (PARTITION BY User,MemberID) AS TotalAdditionalContribution,
COUNT(CASE WHEN AdditionalAmnt  > 0 THEN FamilyID ELSE 0 END) OVER (PARTITION BY User,MemberID) AS TotalContributors
FROM View
)t