You can quicky change ur "temporary wallet" solution from coinbase to blockchain.info. Blockchain.info allow you to import private key from what i know.
Then you can send from blockchain.info back to ur coinbase account or use it all along.
You decide, make ur choice.
I'd recommend staying away from any of these Web or online wallets. They hold your bitcoins for you and you can request them from them. It's the exact opposite of what bitcoins are, an unbanked decentralized currency. I will never use blockchain.info after they stole from me.
If there is no reason to trust anyone, why trust anyone? They aren't a bank. If your bitcoins are stolen by hackers or an inside job you're going to be on the wrong end of an 'oops, sorry' email.
Try electrum or mycelium. Stick with them and don't send any funds to a web wallet. There's no reason to trust them, so don't.