It doesn't sound like you can improve your diet much. If you aren't eating fatty fish like salmon or tuna twice weekly, you might do that. Or you could start taking a fish oil supplement. Then try to get more cardio exercise. For many people that helps to bring the HDL up higher, so the ratio looks better. I think those things are probably all I would do until my next lipid test, but if you were really concerned you might also consider taking some flush-free niacin. I wouldn't take any more than 250 mg at this point. That might just be enough to improve your numbers a little with a minimum of risk of dangerous side effects.
The birth control pills are probably what is making the difference between your current good lipid panel and what would otherwise be a superb one.