Nazar,
First of all where are you presently residing?
Normally, All you need to do is go to a Bank in your home Country and ask them to issue you a Bank Draft in Canadian Dollars payable to or to the order of the "RECEIVER GENERAL FOR CANADA" and send it in with your application.
Inquire from the Bank what the rates are.
Dear Bobby,
Thanks a lot ... really appreciated ...
I am applying from Pakistan and have USD currency account as well as Euro and Pakistan Rupee .... I will go to bank and do the needful
Thanks again
Nazar