Your current diet regimen is most likely what is causing your abnormal cholesterol levels. Most low-fat diets are also high in carbohydrates. A high carbohydrate diet raises insulin levels which triggers the liver to produce more cholesterol, and better than 80% of the cholesterol in your bloodstream is produced by your liver. The remainder comes from what you eat, but the less cholesterol you eat, the more your liver makes. So, cutting out things like eggs and meat will not improve most peoples lipid profiles. In fact, red meat and saturated fats help to raise HDL (the good cholesterol) levels. Things like polyunsaturated fats, often touted for their ability to lower serum levels of the bad cholesterol, also lower the good HDL cholesterol (you don't here this fact often mentioned though). And high carb foods like sugar, bread, pasta, potatoes, rice, corn, etc. will raise triglyceride levels which have a strong independent association with heart disease. Another thing to avoid is hydrogenated vegetable oils found in margarine, shortening, and most processed baked goods (just read the labels on any loaf of bread or bag of cookies). These "synthetic saturated fats" also contribute to abnormal lipid profiles and are suspected to be a major contributor to the recent rise in heart disease and diabetes.
My advice is to adopt a low carbohydrate diet that stresses whole natural foods including meat, fish, poultry, eggs, dairy, non-starchy vegetables, and limited low-sugar fruit. A good book on the subject is "Protein Power" by Drs. Eades. They discuss the mechanism that causes elevated cholesterol in the book and the way to correct it.
The tragedy of science is the slaying of a beautiful hypothesis by an ugly fact. T H Huxley