It is important to work on getting private clients. There are many ways to get private clients besides on this board. In fact, I would argue that most of the people hiring here, including myself, pay too low. I pay what I can afford, and what the market bares so don't take that wrong. But if you want to make more, go to places that people will pay more.
At first, it may seem impossible -- everything takes time, and dedication and marketing is a never ending job for the freelancer. Create your own website that gets good traffic. Use all that
SEO knowledge to your advantage. Join groups that have people there who need what you have to offer.
Price your work accordingly. If you are a great writer, price it as if you're a great writer. Underpricing yourself is one of the main reasons people find themselves working their fingers to the bone and burning out. If your writing needs a lot of editing and work, charge less but practice and hone your craft.
Consider writing for offline publications. Many local businesses also need writing for proposals, grants, white papers, and copy writing. Create great marketing materials for yourself, join your local chamber of commerce, alumni associations or other groups and give out your business card.
Tell people what you do. I've given out my business card while at the doctor, in grocery stores, and elevators. I try to talk to people wherever I go and tell everyone I know what I do.
You can do this! It's great that you're making 400 a month, that's at least grocery money! It can be really difficult when you have little kids under foot. I can still remember my now 20 year old daughter crying when I got near the computer. At that point I made a choice for a while to put her first, my income went down, but as she got older it went up.
Best wishes!