Right now both coins are still in the same address with the same balance and it's been like that since August 1st.
Your current wallet will be connected to the Bitcoin network, not the Bitcoin Cash network.
Your private key or seed will be valid on both networks, but you'd need a Bitcoin Cash wallet to access the Bitcoin Cash part.
What you need to do is move the Bitcoin first into a new Bitcoin wallet that you control with new private keys or a seed. Most people regard six BTC confirmations as more than enough and that should take about an hour.
Once your Bitcoin is safely moved, it's now untouchable and there's zero risk of it being lost to the Bitcoin Cash network.
You will still have access to your Bitcoin Cash with your old seed which is the same balance and address as your Bitcoin was on August 1st as it hasn't moved on that network yet.
Import that seed into a Bitcoin Cash wallet such as this -
https://electroncash.org and as long as it's connected to the Bitcoin Cash network it'll be there waiting for you.