Don't be surprised if a moderate change in diet has almost no affect. Everyone's body chemistry and genes are different. My cholesterol was below 200, but my ratio was so-so, even with exercise. Doc put me on a very small dose of Zocor (10mg) which brought it down to about 100. I'm smart on diet, but don't watch every single fat molecule. My trigycerides were a moderately high 400, and a small dose of Zetia (10mg) brought those down to about 130. I believe the way Zetia work is to block the body from absorbing the bad stuff in the first place, so it just goes right on through you.
I don't like taking medications either, but my flight surgeon is really sold on the benefits of these things. He says the benefits are such that there's serious consideration being given to prescribing the Zocor class meds to those with even normal cholesterol levels.
Talk to you Doc some more about meds if the diet doesn't produce good results for you.