Question about target calories per day

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First off, I apologize as I know there is a lot of topics about this already. I have been dieting, or as I prefer to call it "making healthy choices" for a few months now. I am fairly thin already but had a gut that I really wanted to lose. My goal was to lose 20 lbs. total (I lost 10 before using myfitnesspal). I am just about to my goal now, and getting to a point where I don't need to lose anymore weight.

Anyhow, based on my BMR I am supposed to net ~ 1600 calories a day. But I have come far from reaching that on a daily basis. In the past 30 days, only once did I hit 1600 calories and that was only because I went out to dinner with the wife and then had 2 or 3 martinis. I typically "net" about 1000 calories a day. Eating ~ 1300 and then exercising for a typical burn of 300 - 500 calories a day. I assume this isn't healthy which I why I wanted to post and get some feedback.

I can't really imagine eating 1600 calories a day, every day. I also don't want to be so skinny that I am malnourished. Now that I am approaching my target weight, I want to maintain it and tone my body. I typically do a 30 min walk 5 days a week. Then 30 min elliptical/run 3 times a week and 45 minutes of karate 2 times a week. Averaging 5 days a week of pretty active exercise. I am wondering If I should cut out the cardio now and focus on strength training? Also, how important is it to maintain 1600 calories a day?

Thanks in advance for your advice.