I have bitcoin in blockchain.info (where i control the private keys) before 25 Oct.
Which exchange/wallet can i use to split the bitcoin into BTC and BTG so that i can sell them separately before 1 Nov 2017?

I have Bitcoin stored on blockchain.info before the fork.
If I transfer the Bitcoin to coinbase to sell, would i lose the Bitcoin Gold too?
What is the correct way to retain Bitcoin gold while selling the Bitcoin on exchange, since they all share the same private keys?