it sounds like maybe you're going to miss your BF time, and my question is why don't you continue BFing? I know lots of women want to stop by a year for any number of reasons. I personally have chosen to stop BFing when my kids are ready to stop instead of when I want to. I'm not judging you in any way, it's just that a lot of moms don't realize that not only is it OK to BF beyond a year, it's very beneficial for the child in so many respects. If you haven't thought about it, maybe you should!
Back to the original question, as for caloric intake, unless your child is still using your milk as her main source of nutrition, you're not using that many more calories. The 500 number generally comes from the peak of milk production. If you wean gradually (that would be best anyway) and you don't see an increase in your weight, you're probably adjusting your diet accordingly and may not gain when you remove the last feeding.
Then again, some women retain a little weight while BFing and then lose 5-10 pounds when they stop.
If you remain active by doing cardio and strength training you will probably retain your physique.