Welcome and good luck
I guess first of all you need to work out your best plan of attack. What is going to work for you. You need to educate yourself on the type of plan your looking to follow. What things to watch out for along the way...etc
Do you plan on doing exercise to help you along and if so you should be looking at something you can maintain. Sure the more exercise, the faster you'll lose the fat and build muscle, but you want something you can manage, not something that when you stop you'll need to address your diet more as a result of the change in activity.
I would say if your looking to reduce the high BP you need to reduce or try and cut out carbs. Either on a calorie counting diet or a low carb/ high protein diet. Sugars are probably the biggest issue, either directly or indirectly as in the form of carbohydrates. Carbs turn to sugar if you don't burn them off, that's why reducing your carb intake will make a big difference. But also increasing protein will help as it's good for your internal organs and muscles.