Wow, if you have not done so post in the Bell Canada Direct forum and see if they can help you increase your profile speed, as speed goes up instability increases so you might be as high as you can go. You don't mention which modem you have, however if it says Nortel that's likely the problem (the Nortel Modem only does 1 Meg), best to let Bell Direct know what hardware you have.
Bell Canada Direct Link:
»Bell Canada Direct
Regarding your question about getting secondary service which is concurrent with Bell, most homes have at least two POTS pairs so you probably could get a second phone line set up. You don't need subscribe to phone service; most companies including Teksavvy and Bell offer a "Dry loop" which is DSL service minus a dial tone. The down side is there is a fee for a dry loop however it is less than having phone service. Not sure what Bell charges for a dry loop, however TS price is posted on their website so check there for complete pricing.
Shame that there is no cable service in your area, while Rogers plans are ... unaffordable some of the other ISP companies offer cable service with better rates.