Count of ID and cost per month

SELECT pr.PurchaseRequestId,
pr.DateRequested,
   DATENAME( month, pr.DateRequested) AS DateRequested,
   SUM(prl.TotalCost) AS TotalCost,
  COUNT(pr.DateRequested) AS CountOFPRIDINMONTH
  FROM dbo.PurchaseRequest as pr
  LEFT JOIN dbo.PurchaseRequestLineItem as prl
    ON pr.PurchaseRequestId=prl.PurchaseRequestId
 WHERE prl.TotalCost IS NOT NULL
 GROUP BY pr.DateRequested ,pr.PurchaseRequestId

Result:

PurchaseRequestId    DateRequested    DateRequested    TotalCost    CountOFPRIDINMONTH
885                           2013-05-21              May                       100.00     1
886                           2013-05-21             May                         100.00    1
894                            2013-05-21            May                      2470.00    4
918                           2013-06-12            June                         240.00    1
919                        2013-06-12  7          June                         250.00    2

I am looking for the result as

MONTH   CountofPurchaseRequestIdinMonth   TotalCost

MAY          6                                                       2670

June         3                                                       490

How can get this ? can anyone suggest me please

Thanks