Hi Aasai,
Thanks for your feedback. For this problem, as far as I know, workflows cannot be copied and pasted directly within SharePoint. I checked the article you provided, it uses a workaround to move the workflow (which is not official supported), it applied to the situation moving workflows within one site collection, but not between different farms.
In your situation, to move the workflow, as a possible workaround, you can try to export resource site as a template, and then import the site template to SharePoint Online, you can use the template to create a new site in which the workflow is contained.
In addition, during my researching, you may find the discussions in the following threads helpful (Note: it doesn't apply to SharePoint Online):
http://social.msdn.microsoft.com/Forums/en-US/sharepointcustomizationlegacy/thread/442eb024-29c5-44e1-91ea-97d37aa5cec2/
http://social.msdn.microsoft.com/Forums/eu/sharepointcustomizationlegacy/thread/b034a5ba-abc8-4396-99cc-ce38f9eb7747
If my above information doesn't help you, please let me know.
Best Regards,
Evan Zhang
