Finding it hard to eat ENOUGH calories now.

Since I've started MFP I've lost about 21 lbs in 3 months, I've been the same weight for about 2.5 weeks now so I guess I"m at a plateu. I do 4-5 classes of 60 minutes a week of Zumba or Cardio Kickboxing and do an ab/core strength class 1x a week and I am an office worker so I had my settings at sedentary. I was at 1200 calories a day and the days I do my classes I figure them around 600 per class (low end of what people say they burn). Some days I'd go over, and some days I'd be under, trying to keep a good average for the week, trying to eat all of my excersise calories back on a weekly average. I even did some "cheat" days during special events where I was around 2K calories.

Now I'm reading I should maybe try eating more so I kind of upped it about 200 a day but unless I go and eat crap I find I'm finding it hard to get my calories in. Should I just splurge on the foods I like more, or what? give in to the Mcdonald's fries?

I must add I am kind of a picky eater, I don't like tuna, oatmeal, sweet potatoes, most cooked veggies, which are some common foods in "diets" I do like raw veggies and lots of salads, which I tend to eat alot and I use full-fat dressing usually so I pad my calories. I only use "real" butter, not margarine also, and only real mayo if/when I feel I want to eat it.

Any suggestions?