The best thing would be to ask your physician to refer you to a nutritionist or dietician who could help you plan meals that would be low in fat, with regard to your gall bladder condition, and still nutritious for pregnancy. They will work with you when it comes to dietary preferences too :)
Until you've gotten that referral though... just keep in mind that the best dishes are the simplest, using few sauces, especially those containing cheese, cream and oils. Use information from your OB-GYN to determine how many servings of each food group you should have each day for your baby's health. (Generally this is a pretty normal diet with one extra serving each of protein, calcium/dairy and yellow/green veg/fruit.) Make sure you are taking a prenatal vitamin supplement.
If you like stir fry, this is a great way to have your protein (skinless chicken, lean beef and yes, even pork of it's lean) with a ton of veggies (broccoli, red and green peppers, julienned carrots, yellow and green squash, green beans, peas, you choose your own combinations) and just cook them quickly in a wok or large skillet, using only a thin coating of olive oil on the pan. Start with the items that take the longest to cook and end with something that requires little cooking, like snow peas or bean sprouts.
For seasoning, just a little soy sauce, salt and pepper... can throw in a little ginger if you'd like. If you want it to seem "saucier" then mix a little cornstarch with your soy sauce before adding it in toward the end. Serve this with some brown rice.
Salads are also a great way to get lots of veggies, a little protein, just avoid cheese (or use lowfat cheese) and use fat-free salad dressings or lesser amounts of the lowfat versions. Consider making your own salad dressing using a 6oz can V-8 juice, 1tbsp balsamic vinegar, salt and pepper, and 1/4 cup lowfat cottage cheese thrown into the blender. Sounds strange... it's very tasty :)
Pastas are great as long as you have them with lowfat sauces and additions. Try simple marinaras with a little parmesan on top. Parmesan is actually a very lowfat cheese. Steam your own selection of veggies and have them with the pasta, with or without sauce. Avoid alfredo sauces because they're high in fat content.
When you choose your dairy products, choose skim milk and skim milk or lowfat versions of cheeses, yogurts, sour cream etc and then use sparingly. (Keep in mind you will need to have enough fat-free yogurt or skim milk to fulfill your calcium requirement during pregnancy.)
Consider having a fat-free smoothie for breakfast, using 8oz skim milk, a frozen banana (cut in chunks) and a handful of frozen strawberries. Whiz that up in the blender and it's very satisfying, and fulfills one calcium and two fruit units for the day.
Please do seek counseling and suggestions from a registered dietician or nutritionist. If you use the health department for your prenatal care, they have folks there who can advise you as well. Best of luck to you and congratulations on your impending arrival :)