I know that the transaction was already confirmed, though in the future if you ever have this issue I would suggest:
1. Downloading electrum right away (if you do not already have it on hand, which is handy in general and for these kinds of situations).
2. Exporting the private key from bitcoin core and importing it to electrum (from memory you can go to the developer console and use dumpprivkey).
3. Replace-by-fee to an address of your own.

The sad part about this is that I saw this thread this late. You were lucky that your fee was as low as it was to be able to have as much time as you did to solve the problem. It's a shame that you could not solve it in time...I'm sorry for your loss.

Also, you really should be keeping your client up to date. Using a client out-dated by over 2 years for any application let alone one that is finance-related is generally not the best security practice.