If I had to bet the farm on what's going to happen, I wouldn't assume a long sustained increase against the USD.
The increase in the Cdn dollar is mostly due to the USD tanking. I think the USD is likely to continue to drop against other currencies worldwide.
BUT there is only so low the USD can go before it starts really hurting significant parts of the CDN economy (auto parts exports, cdn manufacturing, lumber, farming, tourism etc.).
Once those sectors of the economy start to hurt the Bank of Canada will be forced to drop interest rates to stimulate our economy, which will make the CDn dollar less attractive for investors.
But what do I know, I can't even balance my chequebook ;-)