oh i forgot to ask, you can travel to Canada with GC ? correct? or do i need Visa for that?
Why would you need a visa ? Remember you are still a US perm resident until the day of the oath when they will ask you to surrender your GC and hand you your citizenship certificate. Don't loose that GC. That's the only thing you have that will get you in & out of the country until the day of your oath.
I believe he meant "a visa for Canada".
No, you do not need a visa to go to Canada regardless of your citizenship as long as you present your US green card to the Canadian immigration.