You have to import the private key. You can do it with pywallet or in one of the online wallets, such as mtgox or blockchain.info.
Usually you use that as a savings wallet because it not practical to keep importing the keys somewhere (and it is safer if you keep it on the paper).
Pywallet imports the wallet into the "official" bitcoin client wallet.dat format, right?
Without importing the keys somewhere, the bitcoins are quite useless since you can't really post them anywhere.