Personally, i would keep rebroadcasting it from as many nodes as i could find, hoping that sooner or later, a miner picks it up and puts it in the block he's currently working on.

If you do nothing, chances are that more and more nodes that did know about your transaction will start removing it from their mempool, in long enough time, it'll be like the transaction never existed... This does not happen if you keep rebroadcasting.