Sheesh, I'm impressed with you! A beginner and practicing 2 hours or so a day? I've played piano my whole life and still play in college, but I'm a complete slacker when it comes to practice. I find it highly interesting that you've chosen anime/video game songs for playing in a piano class. A couple years ago I took Azmaria's theme from Chrno Crusade and put it on piano
As for sight-reading, as said before, it's all about practice. Practice all your scales, major and minors. Get your arpeggios nailed down. Try sight-reading a new piece at least once every day. You may not notice progress for a while, but someday you'll realize that you just sight-read a piece completely through at, or close to, regular tempo without a single mistake. Also, when you get good enough, don't be too proud to start new pieces at ridiculously SLOW tempos, always using a metronome, a classical musician's best friend ^_^