The best way to boost your weight loss once you have a healthy diet is to increase the amount of exercise you do. I was four years post-op when I started running for the first time and that was when I dropped the last 30 lbs.
As for your diet, continue to focus on getting protein first, veggies second, and then whole grain minimally processed carbohydrates if you have any room for them. For instance, an optimal lunch for me is a nicoise salad (salad greens, 3 oz. tuna, 2-3 tbsp. white beans, 1/2 hard boiled egg, green beans, capers, and a light basil vinaigrette). When I want to snack, I'll munch on dry Kashi Golean cereal (tons of fiber, low sugar, and 13g of protein in a 1 cup serving), roasted and salted edamame, or have some yogurt with fruit.
Your weight loss hasn't ended. Sometimes you just need to change things up a little bit. The other posters' advice about journaling your food is great too. I'm 8 years out and still measure and journal my portions. It makes me feel more sure of the nutrition I'm getting each day and helps me keep an eye on my iron intake.
Best wishes to you!