I have successfully lost weight sticking to between 1600 - 1800 calories a day while nursing, with no problems with milk supply. But I have
never had problems with milk supply. If your baby is at least six weeks old, your milk supply is pretty well established.
Also, take into consideration that you need to stay well hydrated and get an adequate protein intake. Nursing moms should get at least 75g of protein a day; it is a very important nutrient when it comes to breastfeeding. Looking at your food log, you're probably a bit low on the protein side. It's actually a fairly easy nutrient to add; you don't need to get it from just meat. Have a glass of lowfat milk with your breakfast, a piece of cheese or some nuts for a snack, that sort of thing. You want to get some healthy fats too, and nuts (especially pecans & almonds, but
not peanuts) are a good source.
And don't forget that there are things other than food that can help with milk production. Never underestimate the power of laying down and snuggling with your baby.
When I first had my younger daughter & was paranoid about the supply issue, I supplemented with brewer's yeast (you can actually get it in capsule form at Wal-Mart), & you can pick up Mother's Milk tea at most health food stores.