Veganism and cholesterol?

I am on a vegetarian/vegan diet for my cholesterol levels. I am trying to lose about two pounds within the next 2 weeks week and a half. In the few weeks I plan to lose five. I am seeing a specialist doctor and regular doctor. I need to lose about forty pounds. It was 262 last time and god forbid it is higher. My question is apart from losing weight and exercising/diet alone would it lower my levels significantly if I follow a vegan diet within the next month or more? I do drink soy milk but it has no cholesterol anyway. I am going to try no diary and eggs and meat for a while or a few months at least or within the next three months. And if my cholesterol lowers significantly then that is good for me. Another question is, How many miligrams of cholesterol can a person safely ingest a week and be safe from the high levels, such as 15 mg?