That seems like a good amount depending on the length of your stay. Even if you aren't common law you can still list someone to help you financially. I did this on my first extension application. I had some money of my own but I still stated that my b/f was financially responsible for me. I asked for 8 months my first extension. I had $2000USD at the time and included all the documents to show that he would be able to pay for my stay.