I've submitted you txid to
https://confirmtx.com/ and hopefully it should accelerate in the upcoming blocks. You can check the same and it should notify you that it's already in queue.
For future usage you can utilize either confirmtx or viabtc's tx accelerator. It seems like the current fee to get into the next block is about 190 satoshi's / byte. So considering your transaction that should've been 190*258 bytes = 49020 satoshi's which is roughly about 5-5.5$ I guess. I'm not sure if that was the recommended fee at the time you had performed the transaction, but it does seem a odd as to why it hasn't confirmed yet. Even with $3 worth of fee's it should've confirmed in about 4-5 blocks. But hey, maybe I'm not so sure about my calculation on that.
