I have B1/B2 visa, 5 years multiple entry visa taken from my home country Bangladesh. I have come to USA for the first time in February 2014 with my baby of 4 years old. Now I want to visit Canada as a tourist. Is it possible to take visa for Canada for me & my child from USA?
I think you are already aware that you do need a visitor visa for Canada (you wouldn't need the visa if you were a permanent resident of U.S.A).
It also states:
Is it possible to take VISA for Canada for me & my child from USA?
Yes, it is. In fact you can apply in two ways:
If you have any further doubts, it will be best to phone or email the nearest Visa Application Center- contact details and locations found here.
Immigration and Citizenship Canada has a website where you can find out your visa requirements for visiting Canada. If you answer the questions it will tell you what your requirements are. Here is the website to apply for a visitor visa. Application can be done online, so it seems unlikely that you need to be in your home country.