First of all, get your wallet seed (Wallet -> Show -> Seed) and save it somewhere. Also backup your old wallet file to avoid any possible issue.
Now:
1. Download the latest Electrum[1] version (v3.0.2 as I'm writing this);
2. When creating your new wallet choose Standard Wallet -> I already have a seed -> Paste your old wallet seed -> Next;
3. Done! Now you can spend/receive your coins.
Don't forget to save/write down your seed. Without it, you won't be able to recover your coins if anything happens to your device/wallet file in the future.
To claim your BCH:
1. Download Electron Cash[1] (Electrum fork for Bitcoin Cash);
2. Open it and choose the same wallet you just created above (if you don't file the wallet file, look for it at %appdata%/Electrum/wallets).
3. Done! You should see your BCH balance and be able to spend them.
[1]
https://electrum.org/#download[2]
https://electroncash.org/#download