Monoprice 105502 6-Feet 32AWG Mini DisplayPort Male to Female Extension Cable - White
If you can't replace the cable you have with a longer cable the best solution is to extend it. Monoprice offers Mini-DisplayPort extension cables to extend your existing cable for situations were the cables just are quite long enough to reach. DisplayPort v1. 1 Does not support audio. Note Some models of Mac's the connector may block access to the adjacent USB accessory port.