Windows administration and Sql Configuration are two integral part of SharePoint administration. If you can master these subjects, then it will make your life easier as SP admin. As Kundan mentioned, if you can get certification like MCSE ,  then you will be ideal SP Admin. But don't get discouraged thinking that every employer will ask you to get Certification before they offer you job, SP certification is not a piece of cake and employer knows not everyone has time for certification. Good luck.