Lighting-wise you could do a few things. The evening light idea is good, but if that is evening sun, then there would still be a lot of blue (or more commonly purple) light coming from the sky to fill. The uplighters are way too powerful, which is why the picture looks out of balance. They should look quite insignificant in comparison with the sunlight. Also, if there were that amount of light on the building, there would be a lot more on the clouds in the sky.
I will say this on a line by itself – There is nothing wrong with parts of your image being dark!
I say that because there are so many people who are averse to dark areas on CGI, yet real dramatic photos often have dark areas. If you fill every part of the screen with light, it will look bland.
I personally would try to change the viewpoint, too. You have a very architectural view here, rather than a dramatic one. You could view it from closer, looking along and up at the building, or down from above, or whatever, but your current composition is a bit too symmetrical.
Personally, I would model the light you are aiming for with a dupliverted sphere of very dim purple lights, and a second one with no top, to mimic the sky, which tends to have more light from the edges at that time of day. Then a single orange one for the sun, surrounded by an orange area light to mimic the glow off the clouds near the sun, and make the uplighters blueish. They should reach only one floor at full intensity, fading off before the second. I would also add a camera flare and/or halo on the uplighters. If you model anything on the opposite side of the street, then you will also need to add some area lights on the front of the building where the light is hitting it, to provide the reflection off the building.
Put something in the way of the sun, to throw a skyline onto the front of the building, and move the camera down to street level, looking up at the lit face in the left 2/3 of the image, and the dark side of the building, lit mainly by sky purple and the small uplighters/streetlights, in the other 1/3. The dark/light contrast and the orange/purple against the blue/purple colours will break the image up and emphasise the time of day.