Without knowing your weight, height, or current activity level it's hard to have any idea where you should start on as far as calories.
Personally I count calories and use an online program to help determine if the fat, protein, and carbs are at the correct levels. (They show the amount and percent of calories I get from each group.) I also am hesitant to suggest programs like Jenny Craig, Weight Watchers, etc because I've seen my mom drop out of all of them and just pile the weight back on. You need to learn how to eat and what to eat, then make that a lifestyle change. They may work for some people, but on a whole I just don't think they're enough when it comes to teaching you.
Now, not knowing where you are right now all I can say is first stay away from anything in a box, wrapper, or Styrofoam container. Most of these are very processed foods and can contain lots of starches and sugars which (diabetic or not) is pretty bad for you. This include obvious fast food- but also hamburger helper, generic white bread, and lean cuisine frozen dinners. Also do your best to avoid canned foods. Meats, soups, and veggies can have tons of sodium added to them and a lot of their nutrients kills- really you just don't need that. Try to have all your foods be more natural and as close to "right off the tree" as possible. The winter time can be hard, but frozen over canned at the very least.
Personally I'm also pretty against fake sugars. The yogurt with splenda was the only type my diabetic grandma could safely eat and she needed the probiotics, so I understand that sometimes it's unavoidable. But limit them. Diet soda isn't healthy, neither is filling up your diet with the other "diabetic friendly" confection. A treat is ok, but a saying it's ok as a regular staple in your diet makes me nervous.
You need lots of fiber at least 30 grams. These are in fruits like pears and apples, in fresh veggies like broccoli, and in things such as psyillium husk and oat bran. Personally I add a tbsp of psyllium husk to my oatmeal every day and it has done wonders for my tummy. This can be found at many health stores, just ask. Also some of the added fiber supplements like Metamucil and Benefiber use oats and psyllium husk -and if you look carefully don't add sugar. Add some to yogurt and you can easily make sure you're getting enough in your day.
Second drink plenty of water. You need 1-2 liters in a day. So get a one liter bottle, keep it on your person, and do your best to fill it up at least once.
As far as what you should be eating think of a dinner plate half of it should be veggies (much more carrots, broccoli and spinach over starchy veggies). Avoid covering these with sauces and look for what's in season -that way you're getting fresh veggies. For the other half of the plate, 1/4 needs to be a lean protein. This can be chicken breast, fish (oily like salmon, a white fish, or something like prawns), lentils, nuts, low fat dairy, etc. The remaining 1/4 of the plate should be whole grains- such as brown rice, barely, oats, whole grain bread (not the cheap we added color to this bread to make it look healthier-but real whole grain). This is a good visual for what your meals should look like. In addition to this you also need 2-3 serves of fruits in a day.
It's also important to eat every few hours. So have your small meals and throw in a couple snacks in the day. These can be something small like fruit and cheese, yogurt, nuts, boiled eggs, etc.
Finally last bit of advice, because you are over weight with high risk for diabetes and possibly heart disease your dr should be able to convince insurance companies to pay for you to see a dietician. Usually all you need to do is ask.
Do you have a thyroid disorder? Always make sure thyroid levels are adequate before starting on any diet.
Since you have type II diabetes in your family, opt for low glycemic foods; those are the ones that will not raise blood sugar quickly, and include lean protein, whole grains, low/no fat dairy, "good" fats, etc.