How to access a blockchain.info wallet's funds from another site like greenaddress.it
You can't move out from blockchain.info to greenaddress.it since they are using p2sh and blockchain not! 

You got many solutions:


Create new wallet on greenaddress.it and send your funds from blockchain.info to that new wallet, You can use some VPN software to access it.
install electrum, easy, lightweight and you can import your mnemonic phrase.