How To Give Certain Task To Paypal After Completion payment

Question

hi Friends
 
I Have a Custom Created Shopping Cart GridView With Some Items Names And Costs And Also Shows Total Cost Of The Items. I Have A Button named "Buy Online". When i click on that button The Total Cost Is Integrated With Paypal and We Can make purchases through paypal or any credit/debit cards. Its All Well n Good. But I Have To Get The Mail Of The Gridview That contains Purchased Items. 
 
My Question Is That How Can I integrate e-mail Credentials to Paypal account by clicking the "Buy Online" Button after the completion of Paypal Payment successfully..
 
pls help me and give some suggestions regarding this problem.
 
thanks in advance...