Medevac pilot reported they flew off course on their departure and received a Low Altitude Alert from ATC as they were below the Minimum Vectoring Altitude.

Narrative

While departing Reno weather was reporting strong winds from the west. I was cleared to takeoff 17L on the Reno one departure. I had the departure input in my flight plan in the FMS and had the I-RNO loc frequency tuned in on nav 1 for guidance on the departure. Just before takeoff on my taxi clearance a new Atis was issued so I tuned the frequency back in to update the latest weather info. I accidentally switched the loc frequency while tuning in the Atis. On departure I encountered a heavy crosswind and windshear -15kts. once I got the plane on the correct path and in a controlled climb; I selected the autopilot. The frequency was changed and the plane was set to nav mode but receiving information from the FMS. I attempted to change the nav source and disengaged the Autopilot as it was leading me in the wrong direction to the west. Fly the plane. As I was making the correction the wind blew me off course and ATC advised. Once I got my bearings; I made an immediate correction and started an expeditious climb. I was advised by ATC for a low terrain altitude alert at 8500. The MVA was 9000 from what I remember the controller advising. I then told them that I swiped the frequency and was correcting course and altitude. In the future I will crosscheck frequency upon entering the runway and double checking that the correct course and navigation source will be selected for a ground-based departure procedure.