I would opt for more grow lights and more convenience if that's easier, so long as they don't burn your plants. The window light helps, but your grow lights should help, too, and probably more than indirect sunlight would, especially if you're using multiple color temperatures.
To illustrate this point, I have some yellow pear tomatoes under a regular 3-way incandescent lamp (with a 3-way bulb on at its brightest from the dollar store) that we just use to light our living room. The tomatoes are under the lampshade. They get very little light from the curtained, north window a few feet from it, but they're doing much better this time of year than the tomatoes getting only light from a south window with a couple pine trees blocking some of the light. Granted, they grew better on summer light (I'm not sure if the summer light was as good, or better, but it was probably close). So, the artificial light is probably going to be more valuable, especially if it's actually designed for plants. I just put the tomatoes there to see how well they liked the light (and not because I thought it was the best place to grow them, although I was running low on space in areas I knew to have enough light). I'm glad I did.
In my experience with less-direct, south sun, if your tomatoes are close to the grow light, they will eventually grow more toward it than the window (unless they're very close to the window), but I'm just using regular non-grow CFLs and my plants near them are on a fold-up table in front of the window (rather than on the windowsill). I imagine something more professional than my regular CFLs would work better. East sun would be great in the spring/summer, but I'm not sure so much for indirect east sun.