Have you had your thyroid checked to make sure it isn't under active? I have hypothyroidism and losing weight is a real struggle for me.
Best thing to do is watch portion sizes. I don't really believe in eliminating certain food groups from the diet (except junk and even that shouldn't be completely eliminated, because it makes us feel deprived).
Most veggies are considered "free", so make sure you load on them.
Knowledge is power. Therefore I recommend that you get yourself a copy of “Why We Get Fat and what to do about it” by Gary Taubes. My guess is you’re still eating foods made with grain that raise insulin levels and thus promote fat storage.
I was so frustrated with not losing weight the natural way. Some may disagree with using medication but this helped a lot. I used Trim Spa, you can buy it over the counter at Walgreens or cvs. This hve me energy and made my appetite smaller, but when I did eat it was strictly healthy. I also exercised on a regular and healthy basis. One pound a week is the healthy weight to lose.
When you say that you work out a few days a week, is it cardio only? If so, try doing 20 minutes of strength training before your cardio workouts. What happens when we get older is that we lose muscle mass, which makes the metabolism slow even more. Don't change your current workouts, but add that strength training--look up tutorials on youtube on squats, lunges, biceps curls, tricep kickbacks, back rows, (female) pushups, chest presses, planks, crunches, etc., and buy some resistance bands and two 8lb weights to start. Don't worry about getting bulky--it's pretty much impossible for women to get bulky from strength training, especially the older we get. Good luck with everything!