Your transaction already has two confirmations. It paid a 0.0014 BTC/KB fee. If you want a confirmation in the next block IMO pay at least a 0.003 BTC/KB fee.
https://www.blocktrail.com/BTC/tx/7f13f1c12349d8fceb6600e3de7f64b5d7a7ac3d9dc2b16cbeac599baa4e2374
This site currently recommends paying a 0.00226 BTC/KB fee, but I'd pay a little more than it recommends to get a really high chance of a confirmation in the next block if the transaction's speed is very important.
https://bitcoinfees.21.co/
https://www.blocktrail.com/BTC/tx/7f13f1c12349d8fceb6600e3de7f64b5d7a7ac3d9dc2b16cbeac599baa4e2374
This site currently recommends paying a 0.00226 BTC/KB fee, but I'd pay a little more than it recommends to get a really high chance of a confirmation in the next block if the transaction's speed is very important.
https://bitcoinfees.21.co/
0.0022BTC/kb is enough for a transaction currently.
If the transaction takes too long to confirm you could contact the users quickseller and macbook-air in order to get one confirmed in future (if the problem arises again) - note, this tx accelerator is also helpful: https://www.viabtc.com/tools/txaccelerator/)
