Do I need to wait for blockchain to complete to use private key elsewhere? As the title says: My blockchain sync still needs to sync 56 weeks, but I want to export my private keys from the bitcoin qt wallet to blockchain.info. 
Is it possible to do that without waiting for the chain to complete and unninstall the program, or do I have to wait?

Thanks!
You can export your private keys (using the dumpprivkey command in the console) without having to wait to sync the blockchain.