Importing private keys is like spending money coins from a paper wallet.

You can import Bitcoin private keys on blockchain.info, so you don't need to download the whole blockhain.

Most wallets (based on qt) can import private keys via the console with the command: importprivkey
See tutorial here: http://dogecointutorial.com/paper-wallet.html

We are sorry that we could not offer blockchain transfers for a longer time. At least this way we can ensure that all customers have enough time to claim their coins. We recommend to transfer your coins to another address (for security reasons) after importing the private keys. Importing a private key does not compromise the security of your wallet.