You or your dad (whoever is sending the funds) need to open a USD account with your bank here in Pakistan. Preferably in a bank with foreign roots like Faysal bank, Dubai Islamic, Al-Falah or Standard Chartered.
Get your cash exchanged from a currency exchange and tell them you need the USD with receipt to deposit in your USD account. They will bring the USD to the branch and deposit them in your USD account and you will give them PKR at the decided rate in cash in branch (this is for your safety and convenient also). If you buy the USD without FBR receipt then you can only deposit less than $10,000 per day.
Once the USD is deposited banks are allowed to send any amount in FCY as long as you have legitimate proof that the money was generated though legal sources.
Give your banker proof about source of funds and he'll wire the funds into your CAD account. Typically takes 2/3 working days for the entire process.
Usually the above 4 mentioned banks don't really pester you too much if the amount is below $ 75,000 and it's a one off transaction.
Local banks like HBL, UBL, ABL, Meezan etc can and will do it for you but they will try their best to keep your money deposited in their bank as long as possible so they create unnecessary hurdles.
Having a good personal banker or a friend/relative who works in the branch you are wiring from helps quite a bit.
Also would recommend that you open a USD account in Canada. That way you will only be charged about $ 50 USD for the entire transaction and will get in USD what you deposited in USD in Pakistan. You can get withdraw in USD cash and get it converted at a currency exchange in Canada or ask the bank to give you a prefertial rate (they give you excellent rates if you convert more than 50,000 or 100,000).
If you wire USD to your CAD account the bank will automatically apply the crappy bank rate between USD/CAD and deposit that in your account. On 70,000 you will lose about 1000 CAD.