Unfortunately, you are out of luck...
2FA wallets in Electrum are a special type of 2-of-3 MultiSig wallet. In normal operation, you are only able to access 1 set of the 3 sets of private keys that make up the wallet. The 2nd set is "hidden", but recoverable
with the seed, and the 3rd set is owned/controlled by TrustedCoin.
You say that you have the private keys for you wallet, I suspect you did this by either right clicking an address and selecting "private key" (or attempting to use the export function). Unfortunately, that will only have given you ONE set of private keys and to be able to move coins from that address, you need
at least 2 sets.
To be able to claim the fork... you
need the seed so you can recover a "2fa disabled" version of your wallet (
as per the guide linked upthread) which restores the the 2nd set of private keys into your wallet file. From there you can derive all the keys required to be able to manually create, sign and broadcast a BTG transaction using "BitcoinGold Core" (as per
the guide).
Additionally, Electrum 2FA wallets do NOT store the seed in the wallet file, nor do they provide access to the seed from within the application, as this would make it possible for a thief who had access to your wallet file + password to bypass the 2FA system by simply restoring from your seed.
So, unless you happen to have a "2fa disabled" version of your wallet file somewhere, the only thing I can suggest at this point is that you contact TrustedCoin (
https://api.trustedcoin.com/#/contact-us) and see if they would be willing to sign a partially signed
BTG transaction for you.