Jung - You are doing the right things, keep with it. Most people have to be shown an item multiple times to consider making a purchase, so continue to promote your calendar on your other art communities, social media, email lists, and all other marketing efforts. You are a talented artist, keep trying.
We sell calendars every day for artists on ArtWanted, and many of our members have already sold dozens of calendars. The trick is to continue to promote the calendar to the fans that already love your style of art. Good luck.