Visitor Visa extension....Need help

[Pisa]

Hi

Currently My inlaws have come to US for the second time. They can stay here till Sep. We are planning to apply for their extension for 6 months.
It is mentioned in this website that, we need to submite the air tickets to USCIS.
Is it the old ticket or should we apply for a new ticket (with extended date) and give them

thanks for all your responses inadvance

[immihelp]

New ticket with extended date.

[Pisa]

B2 Extension

This website is of great use and thanks a lot to the team who maintains it very well.
I have two questions regarding my in-laws B2 extension.
1. In the sample I-539 given in this site, it is mentioned that 'Affidavit of Support (I-134) is enclosed with I-539'. But it is NOT listed in the documents to be sent to UCICS. Kindly clarify if we should send I-134 also.
2. Also, its mentioned that we have to write a letter explaining the reason for extending the visitor visa. I want to know to whom this letter should be addressed to. Can you post a model letter for this one also ?.

Kindly help,
Pisa.