Your camera is not supported by LR 5.7.1
You can either
- Purchase Lightroom 6.1/Lightroom CC 2015.1; OR
- DOnwload the FREE Adobe DNG Converter version 9.1 or later and use that to convert your RAWs to DNG, which can be imported into Lightroom 5.7.1
Well there is no Camera Raw update for Lightroom 5.7.1. You would have to upgrade to Lightroom 6 or Lightroom CC or you can use Dng converter
You need to follow the advice of the other responders, but just to clarify. Each version of Lightroom has its own equivalent raw processing engine e.g. LR 5.7.1 has the equivalent of Adobe Camera Raw 8.7.1 and LR 6.1 has the equivalent of Adobe Camera Raw 9.1.