All right, here's my opinion... Despite the fact that you said you want a small change, I have a few suggestions that you could either combine or try seperate for a smaller change...
Go darker. A chestnut, as previously mentioned, would look great. Just a light brown color, and THEN maybe a few highlights.
Go with some side bangs. It looks like maybe you have some, but they're tucked under. Either it's that, or you just have you front stranges behind the ear. I think some side bangs would look excellent with your face shape.