Urgent: help regardin visa extension

[007007]

hey,
my I 94 ll expire on oct 16. rt now im at vancouver, canada. should i return my I 94 and ask for new one or do i need to file for extension of visa?

kindly help me

[007007]

i left usa on 25th jul but i still have valid 1 94.
someone, plz help..

[007007]

somebody..plz.
im goin to vancouver border tomorrow..but some inputs ll be highly appreciated.