Manda81 - Just to clear up the couple remaining questions you had:
1) Electricity is same as USA/Canada so no converters needed.
2) Gas prices in Jamaica are a little confusing for us Americans because is priced per liter (and of course in $J), which we are not used to - I forget whether Canada uses $/Gal or $/L.
For doing in-head calculations, using 1Gal=3.785L, and about $85J-$1US - you just take the posted Jamaican gas price per Litre, divide it by 100 and multiply by 4.5.
So for instance if price is posted as $100J - in-head calculation makes it about $4.50US/Gal - pretty easy.
That's about what the price was when I was there in March - so Jamaican gas prices were about 25% higher than in USA, at least for me in Ohio. Maybe someone else can post recent prices?
3) Your budget of $75,000J for the week should be good, assuming you have pre-paid for hotels. That works out to about $US125/day.
Of course you could easily blow that budget on high-end dining - but it sounds like you plan on eating where the Jamaicans eat, and splurging just a couple times.
Near the end of your trip, if you happen to find yourself running low, you could pay for gas and some food with credit cards - conserving cash for the small places that don't take credit cards. You actually get the official conversion rate as it fluctuates throughout the day - which is a great deal. Of course if your credit card charges the foreign transaction fee, only a few don't - that sucks - you still have time to order one that does not.
4) The reason everyone says to use cambio or bank and exchange dollars for Jamaican - not airport, hotels, restaurants, merchants - is that cambios/banks give closest to official exchange rate.
Any other merchants can choose whatever rate they want - and frequently do.
So even if the official rate is say 84-1, a merchant might just give you 75-1 and not have it posted anywhere prominently. It's not illegal or a rip-off, just the penalty you pay for not using their currency. And between paying in dollars and getting change in Jamaican, you will be confused and lose on both ends of the transaction.