You're going to have a hard time finding a Sentra unless it is damaged for under $4000 CDN or there abouts. Like most imports, ie: Honda and Nissan they have exceptional resell value years after.
At least you guys are attached to the rest of the country and are just a few hours from the US so finding parts or another car, SE-R (for parts) for that matter is an option. Living in Newfoundland has its downsides besides the weather (28C tomorrow though!!!).
Good luck finding another car though,

Greg