Don't you need to go to Canadian tire next to the Tim Hortens for a new one.
On a serious note.
You will most likely need to have you uncle get a duplicate from whatever agency registers sleds in Canada.
You can get the forms and fill them out but he will most likely need to sign them and be present at the .GOV office you need to deal with.
Here in my state of NJ there is a Form you can get from the DMV that will let you do transactions under someone else's name but it has to be notarized.
Best bet would be to drag dear old uncle out for breakfast than to the .gov office you need to go to.