Hi Aasai,
Based on the research, you can use the Visual Studio to create, import and export to SharePoint Designer. Here are some articles for your reference:
Create, import, and export SharePoint workflows in Visio: http://office.microsoft.com/en-us/visio-help/create-import-and-export-sharepoint-workflows-in-visio-HA101888007.aspx.
Import a SharePoint Designer Reusable Workflow into Visual Studio: http://msdn.microsoft.com/en-us/library/ee231580.aspx.
Thanks,
Eben Liu