There is no direct connection from Winnipeg to Selkirk. However, you can take the line 11 bus to Northbound Henderson at Knowles then take the taxi to Selkirk. Alternatively, you can travel from Winnipeg to Selkirk in around 36 min.
From Eastbound Portage at Edmonton line 11 bus to Northbound Henderson at Knowles then taxi to Selkirk. 55 min $67. From Winnipeg taxi to Selkirk. 36 min $89. From Winnipeg drive to Selkirk. 36 min $4.