I think you need to work on increasing HDL and decreasing TG via a high volume of low intensity exercise and cutting out all fructose from your diet. It's the oxidation of VLDL or LDL (the transporter of endogenous TGs) or LDL that likely played a role in your heart attack. So long as you have elevated TGs, you likely have a Pattern B particle size since the synthesis of VLDL in the liver soaks up cholesterol and results in LDLs that contain less cholesterol and are thus smaller in size. These smaller lipoproteins can much more easily become trapped in the arterial linings.
You should also make sure that you're taking vitamin K2 in order to pull any calcium that may be in your arteries out and deposit it in bone. Additionally, you probably should not consume dairy until you do this, as more dietary calcium is working against you. That may have been a factor in your heart attack. As far as the rest of your diet goes, I would increase fat from grass-fed red meat and shoot for a total cholesterol of 200-240.
Edit: That walking would be far more advantageous if it were in the fasted state.