Notices of your Perth art exhibition can be posted in The Perth Calendar. It's free and first on major search engines for "calendar perth". It's my volunteer contribution to art in Perth.
Performing Arts Perth
Promotion of performing arts in Perth is offered free to Perth musicians, Perth dancers, Perth actors, and anyone wanting free marketing of performing arts in Perth via THE Perth Calendar of Events where you can post Perth performing art gig dates, photos and links to your website.