When your transaction failed, it was automatically returned to your wallet on the blockchain, minus the gas spent on the transaction itself. If it isn't being reflected in MyEtherWallet, it's probably because it hasn't resynced with the network yet.
When a transaction get sent in ethereum, one of the following MUST happen:
- The transaction completes successfully, and the recipient has the ether they were sent.
- The transaction is aborted, and the full amount, minus gas cost, is returned back to the origin address.
There's no intermediary -- it's just that clients that aren't synced don't know the execution status of the transaction yet.
More curiously, a subsequent transaction from your wallet to the same contract did execute a few hours after the first transaction. Perhaps you don't totally recall this happening, but you sent 0.5 ether that time -- meaning you're going to have less reflected in your balance than if the first transaction went through. Etherscan shows 0.49324782 ETH still in your account.