I echo the recommendation to ask your medical provider for a referral to an RD but I can offer you some general thoughts to help you make choices until you are able to see them.
When one macro nutrient has to be limited, the others have to compensate if calories and nutrients are to maintained. Looking at what macro nutrient a food provides can help you decide what to select and how to increase the other two options that you need. For example, protein sources like nuts also contain significant amounts of fat so they may be great ways to boost your protein but not with your need to limit fat. Legumes on the other hand will provide you with the protein you want while also contributing very little fat. Fat free dairy products would also be protein and carbohydrate focused options that are low in fat. This chart can help you find those items in addition to the carbohydrate rich fruits and veggies that make a balanced meal.
How to Meet Your Protein Needs without Meat
A Guide to Vegetarian Protein Sources www.sparkpeople.com/resource/nutrition_art