I see that you have not activated your license in SiteOrigin Widgets->License. Pls do the same in the WordPress admin area of your site to help receive automatic updates. Pls make sure you hit the activate license button after you enter the license and hit Save changes.
We just released a new update 1.8.1. I hope you have a notification in your plugins page. Can you retry with the same? If that does not help, pls provide a temp login to your site in a private message here and I will take a look.
I see that the license of yours is active now and hence update may work.