Problem With Harvesting Records By Date Spaning The Previous And Current Years

Im working on a make-table query that harvest records for calculation that span a "rolling" 13 week history... my problem is that the query will work if it doesn't have to retrieve work weeks that are prior to the new year. For example, right now is the tenth week of this year so i need to grab the previous 9 weeks of history plus 4 weeks of the prior year. then next week when the query is ran we will be in the 11th work week of the year therefor i will need to harvest the past 10 week plus 3 week of the preivious year. the query works if you don't have to span accross calendar years. here is the SQL of the query below the problem area is in underlined in bold type:
SELECT PORVPHIS.VENDOR_ID, PORVPHIS.VEND_NAME, [Expr2] AS [Fiscal Year], DatePart("yyyy",[DATE_RECV]) AS Expr2, DatePart("ww",[DATE_RECV]) AS Expr1, PORVPHIS.QTY_RECVD, PORVPHIS.PO_UNT_PRC, [PO_UNT_PRC]*[qty_recvd] AS [Total Price], [Expr1] AS [Fiscal Week], IIf([fiscal week]=[LowWeek] And [Expr3]<>0,[total price],0) AS 1, IIf([fiscal Week]=[LowWeek]+1 And [Expr3]<>0,[total price],0) AS 2, IIf([fiscal Week]=[LowWeek]+2 And [Expr3]<>0,[total price],0) AS 3, IIf([fiscal Week]=[LowWeek]+3 And [Expr3]<>0,[total price],0) AS 4, IIf([fiscal Week]=[LowWeek]+4 And [Expr3]<>0,[total price],0) AS 5, IIf([fiscal Week]=[LowWeek]+5 And [Expr3]<>0,[total price],0) AS 6, IIf([fiscal Week]=[LowWeek]+6 And [Expr3]<>0,[total price],0) AS 7, IIf([fiscal Week]=[LowWeek]+7 And [Expr3]<>0,[total price],0) AS 8, IIf([fiscal Week]=[LowWeek]+8 And [Expr3]<>0,[total price],0) AS 9, IIf([fiscal Week]=[LowWeek]+9 And [Expr3]<>0,[total price],0) AS 10, IIf([fiscal Week]=[LowWeek]+10 And [Expr3]<>0,[total price],0) AS 11, IIf([fiscal Week]=[LowWeek]+11 And [Expr3]<>0,[total price],0) AS 12, IIf([fiscal Week]=[LowWeek]+12 And [Expr3]<>0,[total price],0) AS 13, DatePart("ww",Now())-13 AS LowWeek, IIf([fiscal Week]>=[LowWeek] And [fiscal year]<>DatePart("yyyy",Now()),0,[LowWeek]) AS Expr3, [LowWeek] AS week1, [LowWeek]+1 AS week2, [LowWeek]+2 AS week3, [LowWeek]+3 AS week4, [LowWeek]+4 AS week5, [LowWeek]+5 AS week6, [LowWeek]+6 AS week7, [LowWeek]+7 AS week8, [LowWeek]+8 AS week9, [LowWeek]+9 AS week10, [LowWeek]+10 AS week11, [LowWeek]+11 AS week12, [LowWeek]+12 AS week13, PORVPHIS.DATE_RECV, IIf([Expr4]="AS8819" Or [Expr4]="CO1870" Or [Expr4]="GV2510" Or [Expr4]="MC3105",[VEND_NAME],Null) AS ID, PORVPHIS.VENDOR_ID AS Expr4 INTO Tporv

FROM PORVPHIS

WHERE (((PORVPHIS.VENDOR_ID)="AS8819" Or (PORVPHIS.VENDOR_ID)="CO1870" Or (PORVPHIS.VENDOR_ID)="GV2510" Or (PORVPHIS.VENDOR_ID)="MC3105" Or (PORVPHIS.VENDOR_ID)="IM2680") AND ((DatePart("yyyy",[DATE_RECV])) Between DatePart("yyyy",Now())-1 And (DatePart("yyyy",Now()))) AND ((DatePart("ww",[DATE_RECV])) Between DatePart("ww",Now())-1 And (DatePart("ww",Now()))-13));

I hope some one can help me......you can email me by markphillipsii@bellsouth.net or mphillips@dccabinetry.com

thanks Mark