Should I talk about my poor academic performance due to financial situation in my SOP?
With a low GPA, your chances are already quite slim. You need a way to explain it. But it is even more important that you can explain why the institution can expect that you will be a success in the future. Your poor background doesn't help with this, no matter the reason. If your situation can be expected to continue, then it will be especially difficult to convince anyone that your outcomes will be different. 

You have to make a case for the future, primarily.