To upgrade your electrum with your funds intact,
you just have to copy the wallet file from
C:\Users\(username)\Desktop\electrum_data\wallets\(name of your wallet) to a temporary safe place.
[I assume that this is where your portable version's wallet file was based on your statement]

That was the wallet file, that's all you need to transfer your wallet (aside from the seed).
You can put this wherever you want, you can browse it's location in the electrum "Open" menu.

Then proceed with upgrading to a 3.05 (Uninstall the old version if you're paranoid),
Open the new v3.05 Electrum (whatever the variant) and open->find your wallet file.