@mukesh:You are able to use a BLE device with Win 8.1. The example code is shown for the TI Sensor Tag with default programming. The secret is in your notes to tester when you submit your app. Make sure to explain your BLE scenario in the notes to testers. Handle errors when device is not paired or otherwise unresponsive.
Otherwise I would suggest that you purchase the TI sensor tag and use this example. I know 25 bucks US is a lot of money, but the TI sensor is definitely worth it.