What is that you're not happy about? It's a very nice painting. The curtain is lovely and so is the figure. The only thing I notice is the window. It might need more depth.
Maybe darken the curtain a bit with a deep- but soft blueish/purple? I'm not sure- I'd like to see the figure stand out a bit more from the background.
Do you have Photoshop? You can take your photograph and fuss with the colors and look on there till you find what feels right- then do it to the real thing... Just a thought.
I kinda see what you mean about the backgroud, but proably just like you, I really don't what to see it change. It's a great pattern, maybe the color(?), nah, leave it, she is great. Danny