Is there anything specific that you'd like to improve?

From my experience, sight-reading only comes with time. You could get some books though, or read some tips online. These sites have some good tips. http://www.soundfeelings.com/free/music-reading.htm
http://www.melbay.com/creativekeyboard/feb00/earvssight2.html

I used to accompany in a ballet school and that's where I really learned how to sight read- because basically, it didn't matter if you got a few notes wrong, but you had to keep going with the correct rhythm. That's what my piano teacher had always told me, but I'd never really understood what it meant. Once I'd worked there a few weeks I became super confident in the sight-reading department because I knew I could always keep going!

If u want 2 sight read then pick sum music u enjoy, (and already know) and sight read tht. It might b mre enjoyable and u wld kno how it goes. Then it wld b easier 2 kno how well u did on it.

Also 2 help ur fingers my teacher showed me this exercise




But instead of using finger 4 and 5 use ur thumb and repeat again and again with both hand.

well, there's this book that i know.

"BAGINNING JAZZ KEYBOARD"

it starts from basic lessons in sight reading and step-by-step method for learning to play jazz.

u don't need to be a master of keys to learn this book.

just basic piano skills would do.

i hope this helps


<Added>

sory...wrong spelling

it's "BEGINNING" not BAGINNING.

LOL :)

You can find free beginner piano lessons online at Beginner Piano Lessons or if you prefer, you can download 60 free piano online lessons, which comes with a guarantee you will learn how to play piano by ear at Free Piano Online Lessons.

I hope the above help you to start progressing off the 'music plateau' you seem to be in. Also, I suggest learning piano songs you would really like to play. I find with myself, if I am inspired by the song, I get really deteremined how to play it, and in the process, I learn a lot more about music.
You can download sheet music for the most popular piano songs at Piano Sheet Music - Piano Songs

What grade are you in now? after four years i think you should be in at least grade 4 piano, if you arent.. you should somehow switch piano teachers, why cant you switch? If your not in gradse levels, ask your teacher to put you in royal conservatory. I think you should start with a grade that is hard but not out of your reach, i think in order to get better you have to be chllenged. And scales, theres no way around them, if you want good technique they have to be done regularly.

now to sightreading. I havent ever had a problem with sightreading because im blessed with being a perfect sightreader... but, there are sightreading books you can get for every grade. Ide suggest you find music, look over it once and play it maybe twice, then stop playing it. If you do that to songs you actually like, just to hear what it sounds like, you will improve tremendously.

pick a nice piece that you enjoy listening too. you want it to be a little challenging and maybe a contemporary piece. it'll encourage you to want to learn the piece and read further on