extension of b2 visitor visa doubts

[elvee123]

I have a doubt in extending my visitor visa. i desire to extend my stay for 4 months .as per schedule i have to leave before 8th may 2009 and i have return ticket for 3rd may.now i want to know if i apply for extension have i to book another return ticket and enclose the copy for a proof of my departure from usa?
another question if i dont extend but leave this country for India as per schedule in may 2009,can i come back in june 2009? is there any restriction that i should not come back again.As it is i have 10yr multiple visa.
please clear my doubts.:)

[cncd1]

A short stay in your home country is likely to get you a short authorized stay and may result in denial of entry. You would be best to return home before your I-94 expiration and not return for at least 6 months and preferably more. A visitor visa is for visiting - not living - in the US.