dear mayamin,
good reading skill is a result of good training. I think you need to have more time to teach your Ss how to read. while doing so, try to take these points into account:
teach them reading techniques such as kimming, scannig, reference...
use simple and short texts
teach reading as a follow up to the speaking and listenig skills and try to find reading topics related to speaking and listening ones.
make your students predict what the text is about from the litle or the first line/first two lines.
let them brainstorm some idea about the text
let them know the difference between reading for comprehesion and reading for other purposes
find authentic reading texts.
assign reading homework
make reading sheets attractive
may these points be helpful. good luck