If you're absolutely opposed to doing any missions for light side, then you basically have to just continue milling through the missions till some dark side medical supplies missions come up. Personally, while I would avoid doing dark side missions when possible, I still ended up with a total net gain of light side points over time, simply by prioritizing the alignment I wanted, and just accepting the short-term loss from taking the opposing alignment missions. (Semi-related note, once you hit 10,000 light side or dark side points, further light/dark points "above" 10k appear to drain the opposite alignment points from your totals, rather than raising your light or dark side points above the 10k cap.)