How long will it take for me to get my period again?

I am in the early stages of anorexia... and I've finally realized I've gone to far with my obsession with being skinny. I am too thin. None of my clothes fit me anymore. I'm 19, and most people think I'm 15 because I have the body of a 13 year old girl. If I start increasing my caloric intake gradually... from 1200 to 1300 for 2 weeks, then 1300 to 1400 for 4 weeks and so on... how long before I gain a few pounds and get my period again?