Your metabolism will adjust over time - when I lost a lot of weight and was exercising a lot, I had three months where my ovulation was screwed up but then it fixed itself. I ran out of weight to lose and I plateaued, and over time my body worked to fix things.
Now, I know you don't want to wait that long and that is fine. What I would have you do to try and fix things is to up cals to 2000, continue the cardio 4 days a week, and make SURE you are getting the upper level of fat. 60 g a day, and Omega 6 fats may be better for your sway than Omega 3/saturated fats (so margarine, corn, canola, soy oils and NOT animal fats or fish oil or olive oil). You do NOT need to gain the weight back. You need to give your body time to adjust and the minimum of raw materials it needs to fix itself and it will.
You may want to also add in 8-15 mg zinc 3x a week and 150 IU iodine because if you've been dieting quite strictly you may be depleted in these. I don't know that it will help restore your ovulation, this is meant to be better for your overall health.