I am an Indian citizen living in Massachusetts, US on H1B work authorization.
I want to travel for a week to Montreal and Ottawa for which I plan to apply for Canadian visa.
But my situation is that my earlier US visa expired and I renewed my H1B work permit petition and also got new I-94 which is valid till June 2015.
But I dont have the new US visa stamping on my passport as I didnt got out of US.
In such scenario, considering I get the Canadian travel visa, I can go to Canada but I guess I shall require US visa stamping on my passport based on my H1B work permit papers to get back to US.

Can I get the US visa stamping done on my passport in any US consulate in Montreal, Canada?
How/Where can I find the details about what I need to do for this?

Appreciate if you can provide me any direction/help that I can avail in such situation.